The illustrations used in our videos, and the people who drew them.
Some of the figures and symbols in our videos come from openly licensed medical and scientific illustration libraries. Their licences allow us to use them, including in a paid product, on the condition that the original artists are credited. This page is that credit, and it is generated from the same registry that decides which drawings may be used at all — so a drawing cannot appear in a video without appearing here.
Explanatory text and concepts follow the NCERT syllabus; NCERT textbooks are published freely by the National Council of Educational Research and Training.
| Drawing | Type | Credit |
|---|---|---|
| ecg-lead-ii-healthy | data | Bousseljot R, Kreiseler D, Schnabel A. PTB Diagnostic ECG Database (PhysioNet), ODC-BY 1.0 |
| D-glucose-open-chain | figure | Hmxhmx, via Wikimedia Commons - public domain |
| abingdon-tortoise | figure | Mike Weston, Lonesome George, CC BY 2.0, via Wikimedia Commons, cropped and labelled by Chalklet |
| acacia-calotropis-defences | figure | Composite: Acacia thorns by Angela Sevin, CC BY 2.0; Calotropis by Shyamal, CC0; via Wikimedia Commons |
| acacia-phyllode | figure | Wmpearl, Acacia koa with phyllode between the branch and the compound leaves, public domain; via Wikimedia Commons, labelled by Chalklet AI Labs |
| acid-rain-damage | figure | Composite: acid-rain damaged gargoyle by Nino Barbieri, CC BY 2.5; acid-rain damaged woods in the Jizera Mountains by Lovecz, public domain; via Wikimedia Commons |
| acid-rain-gargoyle | figure | Nino Barbieri, Acid rain damaged gargoyle, CC BY 2.5, via Wikimedia Commons |
| acoustic-guitar-photo | figure | Unknown author, Fender California Series acoustic guitar, CC0, via Wikimedia Commons (Piqsels) |
| acromegaly-face-hand | figure | Composite: Richard C. Cabot, typical face in acromegaly, public domain; skiagram of the hand of a patient with acromegaly, Wellcome Collection, CC BY 4.0; via Wikimedia Commons |
| actinomycete-vs-hypha | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| adrenal-zones | figure | OpenStax College, Anatomy and Physiology, Wikimedia Commons, CC BY 3.0 |
| adventitious-roots | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| aedes-breeding-containers | figure | Centers for Disease Control and Prevention, Public Health Image Library (Aedes aegypti eradication programme, Miami, 1965), public domain (US government), via Wikimedia Commons; captions added by Chalklet |
| aedes-larvae | figure | NIAID (Aedes aegypti mosquito larvae), CC BY 2.0, via Wikimedia Commons |
| aedes-mosquito | figure | John Ragai, Wikimedia Commons, CC BY 2.0 |
| aerenchyma-potamogeton | figure | Berkshire Community College Bioscience Image Library, Aquatic Monocot Stem Aerenchyma in Potamogeton, CC0; via Wikimedia Commons, labelled by Chalklet AI Labs |
| aerofoil-streamlines | figure | Dfedra, Wikimedia Commons, CC0 |
| aestivation-types | figure | after Ronse De Craene 2010 (cc0, aestivation panel A-G) and Encyclopaedia Britannica 1911 (public domain, vexillary panel), via Wikimedia Commons |
| afm-rough-surface | figure | Chych, Wikimedia Commons, public domain |
| algae-fragmentation-conjugation | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| algae-zoospore-zygospore | figure | Gustave Thuret (1850), Ulothrix mucosa, public domain; Sandor Bancso (2021), Spirogyra zygospore, CC BY 4.0; via Wikimedia Commons, cropped and labelled by Chalklet |
| algal-flagella-three | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| alien-fish-nile-perch-clarias | figure | Boulenger and Loat (Nile perch, public domain) and unknown artist (Clarias gariepinus, public domain); via Wikimedia Commons, labelled by Chalklet AI Labs |
| allen-rule-foxes | figure | Drew Avery (fennec fox, CC BY 2.0); Jonatan Pie (arctic fox, CC0); via Wikimedia Commons, cropped and labelled by Chalklet |
| allergy-ige-mast-cell | figure | OpenStax, Concepts of Biology (Disruptions in the Immune System), CC BY 4.0 as released before 2026-04-23 |
| allium-tepals | figure | Alex Abair, via iNaturalist and Wikimedia Commons - CC BY 4.0 |
| allosteric-regulation | figure | OpenStax, Biology 2e (Figure 06 05 05), via Wikimedia Commons - CC BY 4.0 |
| alpha-D-fructofuranose | figure | NEUROtiker, via Wikimedia Commons - public domain |
| alpha-D-glucopyranose | figure | NEUROtiker, via Wikimedia Commons - public domain |
| alveolus-gas-exchange | figure | LadyofHats, via Wikimedia Commons - public domain |
| amniocentesis | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py), re-drawn from public-domain plates (see drawn.reference) - owned |
| amniotic-egg | figure | OpenStax, Biology 2e (Figure 29.4.1, amniotic egg), CC BY 4.0 as released before 2026-04-23 |
| amoeba-proteus | figure | Joseph Leidy, Fresh-water Rhizopods of North America (1879), public domain |
| amphibians-caecilian-metamorphosis | figure | G. Bhatta (Ichthyophis kodaguensis, CC BY 4.0) and unknown author (frog metamorphosis, public domain); via Wikimedia Commons, labelled by Chalklet AI Labs |
| analogue-ammeter-photo | figure | R. Henrik Nilsson, 1975 ammeter by Swedish company Clas Ohlson, CC BY 4.0, via Wikimedia Commons |
| angina-exertion-rest | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| angiosperm-life-cycle | figure | OpenStax, Biology 2e (Figure 26 03 03), via Wikimedia Commons - CC BY 4.0; the 'Micropyle' label, whose leader ends on the stigma, removed, and 'Fertilization' re-lettered 'Fertilisation' |
| animal-cell | figure | Blausen.com staff (2014). Medical gallery of Blausen Medical 2014. WikiJournal of Medicine 1(2). CC BY 3.0, via Wikimedia Commons; cropped, title removed |
| annelid-locomotion | figure | Daniel J. Drew, Yale Peabody Museum, Nereis parapodium microslide (YPM IZ 098039), CC0; segments, earthworm and leech drawn by Chalklet AI Labs |
| annelid-segment-section | figure | OpenStax, Biology 2e (Figure 28.3.17, annelid segments), CC BY 4.0 as released before 2026-04-23 |
| anopheles-mosquito | figure | James D. Gathany, CDC Public Health Image Library, public domain |
| anther-lobes-groove | figure | D. McAlpine, The Botanical Atlas, plate V, figs. 6-8, public domain, via Biodiversity Heritage Library and Wikimedia Commons |
| anther-section-corrected | figure | OpenStax, Biology 2e (Figure 37.1.2), CC BY 4.0 as released before 2026-04-23; flattened onto white, and the swapped labels Microspore mother cells and Tapetum exchanged to match NCERT, and a duplicate tapetum leader that overshot the ring removed, by Chalklet |
| anther-wall-layers-ts | figure | Shunmugam ASK, Bollina V, Dukowic-Schulze S et al., MeioCapture, BMC Plant Biology 18:293 (2018), Figure 1 - CC BY 4.0; layer codes EP, EN, ML, T, ME re-lettered in English |
| antibody-structure | figure | Fred the Oyster, Wikimedia Commons, public domain |
| apical-dominance | figure | Snelleeddy, Wikimedia Commons, CC BY 2.5; Dutch labels replaced with English |
| apomixis-routes | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| aquarium-with-fish-photo | figure | Ales Tosovsky, Amaterske akvarium, public domain, via Wikimedia Commons |
| archaeopteryx-berlin-fossil | figure | Daderot, Berlin Archaeopteryx at the Museum fur Naturkunde Berlin, CC0, via Wikimedia Commons |
| art-transfer-routes | figure | CDC, vectorised by Mysid, Scheme female reproductive system, public domain, via Wikimedia Commons (label, vessel and ligament layers hidden, cropped); boxes, arrows and labels drawn by Chalklet AI Labs |
| artery-vein-comparison | figure | OpenStax College, Anatomy and Physiology, CC BY 3.0, via Wikimedia Commons |
| artery-wall | figure | Blausen.com staff (2014). Medical gallery of Blausen Medical 2014. WikiJournal of Medicine 1(2). CC BY 3.0, via Wikimedia Commons; cropped, title removed |
| arthritis-gout | figure | Wang Z and colleagues, The synovial joint in health and in rheumatoid arthritis (CC BY 4.0); Ed Uthman, Gout - monosodium urate crystals in joint fluid (CC BY 2.0); via Wikimedia Commons; panels A-B kept with the pointer lines to panel C painted over, labelled by Chalklet |
| arthropod-jointed-appendages | figure | OpenStax, Biology 2e, CC BY 4.0, via Wikimedia Commons |
| ascaris-life-cycle | figure | CDC DPDx, Ascariasis life cycle, public domain, via Wikimedia Commons (logos cropped, legs removed, British spelling and labels added by Chalklet AI Labs) |
| ascaris-male-female | figure | Servier Medical Art, CC BY 2.0, via Wikimedia Commons |
| asconoid-sponge | figure | Webster NS and Thomas T (2016) The sponge hologenome, mBio 7(2):e00135-16, via Wikimedia Commons - CC BY 4.0 |
| ascus-and-basidium | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| atherosclerosis-fibrocalcific | figure | Yang W J, Fisher M, Zheng L and others, histopathology of progressive atherosclerotic lesions, CC BY 4.0, via Wikimedia Commons; key added |
| atmosphere-layers | figure | NASA Goddard Space Flight Center, Wikimedia Commons, public domain |
| atmosphere-lower-layers | figure | NOAA and Mysid, Wikimedia Commons, public domain (lower part of the chart) |
| autoimmune-joint | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| autonomic-pathway | figure | OpenStax College, Anatomy and Physiology (2013) Fig. 15.5 Comparison of Somatic and Visceral Reflexes, CC BY 3.0, via Wikimedia Commons (cropped, zoom insets removed, labels added); heart: Jerm, Heart anterior exterior view, CC BY 2.5, via Wikimedia Commons; divisions panel drawn by Chalklet AI Labs |
| autumn-leaves | figure | Ruud Sneekes (Unsplash), Wikimedia Commons, CC0 |
| auxin-rooting-cuttings | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| axoneme-9plus2 | figure | Mariana Ruiz LadyofHats, Wikimedia Commons, public domain |
| azotobacter-cells | figure | Dan H. Jones, Wikimedia Commons, public domain |
| bacterial-cell-mesosome-inclusions | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| bacterial-colonies-agar | figure | Megan Mathias and J. Todd Parker, CDC, Wikimedia Commons, CC0 |
| bacterial-flagellum-motor | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| bacterial-shapes | figure | Mariana Ruiz LadyofHats, Wikimedia Commons, public domain |
| bacterium-fission-and-spore | figure | OpenStax, Biology 2e (Figure 10.5.1), CC BY 4.0, via Wikimedia Commons; with Jonathan Eisen, PLoS Genetics doi:10.1371/journal.pgen.0010065, CC BY 1.0, via Wikimedia Commons; cropped and set side by side by Chalklet |
| banana-parthenocarpy | figure | Johnnybam (banana bunch, CC0) and Mohanramus (Yelakki banana cross section, CC BY 4.0), via Wikimedia Commons |
| bar-magnet-iron-filings | figure | Newton Henry Black and Harvey N. Davis, Practical Physics (1913), fig. 200, public domain, via Wikimedia Commons |
| barrier-contraceptives | figure | Wellcome Collection (three contraceptive caps, CC BY 4.0); Tomhannen, Psychonaught and Axefan2 (condoms, female condom, diaphragm; public domain), via Wikimedia Commons |
| basmati-grain-and-paddy-photo | figure | Ajay Suresh, Basmati Rice, CC BY 2.0; Naithik Shetty, Planted Paddy Field, CC0; via Wikimedia Commons, composited by Chalklet |
| battery-hydrometer | figure | Pearson Scott Foresman, public domain, via Wikimedia Commons |
| bean-germination-stages | figure | Wikimedia Commons user Hudbones, CC0 |
| bee-body-regions | figure | OpenStax, Biology 2e (Figure 28.4.6, bee anatomy), CC BY 4.0 as released before 2026-04-23 |
| bee-orchid | figure | OpenStax, Biology 2e (Figure 32 02 06), via Wikimedia Commons - CC BY 4.0 |
| bell-jar-vacuum-buzzer | figure | PhysicsEtc, Wikimedia Commons, CC0 |
| beta-D-glucopyranose | figure | NEUROtiker, via Wikimedia Commons - public domain |
| beta-sheets-parallel-antiparallel | figure | Fvasconcellos, Beta sheet bonding parallel and antiparallel (colour), public domain, via Wikimedia Commons, labelled by Chalklet |
| betel-climbing-roots | figure | Chang Chia-yu (joycjy), Piper betle on a tree trunk, Taitung, iNaturalist observation 146032333, CC BY; cropped, caption added |
| bicollateral-bundle | figure | Berkshire Community College Bioscience Image Library, Herbaceous Dicot Stem Bicollateral Vascular Bundle in Cucurbita, CC0; via Wikimedia Commons, labelled by Chalklet AI Labs |
| bicycle-photo | figure | US Air Force, Around the bend, public domain (US Air Force), via Wikimedia Commons |
| binary-fission-prokaryote | figure | OpenStax, Biology 2e (Figure 10 05 01), via Wikimedia Commons - CC BY 4.0 |
| biodiversity-hotspots-map | figure | OpenStax, Concepts of Biology (Preserving Biodiversity), CC BY 4.0 as released before 2026-04-23 |
| biogas-plant | figure | SNV, Wikimedia Commons, public domain |
| bioreactor | figure | Original diagram by Wikimedia Commons contributor (Telugu translation by Mekala Harika); English labels translated from the Telugu source, CC0 |
| bird-air-sacs | figure | OpenStax, Biology 2e, CC BY 4.0, via Wikimedia Commons |
| bird-anatomy | figure | MarioM, Wikimedia Commons, public domain (labels translated to English from the Portuguese original) |
| bird-digestive-system | figure | OpenStax, Biology 2e (Figure 34.1.6), CC BY 4.0, via Wikimedia Commons |
| bird-keel-beak | figure | R. W. Shufeldt, skeleton of the passenger pigeon, public domain, via Wikimedia Commons; keel and beak labelled by Chalklet |
| bird-pneumatic-bone | figure | OpenStax, Biology 2e (Figure 29.5.2), CC BY 4.0, via Wikimedia Commons |
| birds-on-power-line-photo | figure | Rollcloud, Birds in power line, CC BY 4.0, via Wikimedia Commons |
| blast-furnace-photo | figure | Aciarium, Blast Furnace 1 at Night, voestalpine Donawitz, CC BY 4.0, via Wikimedia Commons |
| blister-copper-surface | figure | Chalklet AI Labs, drawn for this project (figures/pic2_drawings.py) - owned |
| blood-centrifuged-layers | figure | OpenStax College, Anatomy and Physiology (Figure 18.2), CC BY 3.0, via Wikimedia Commons |
| blood-testis-barrier | figure | A. Yu. Kulibin and E. A. Malolina, The Rete Testis - Development and Role in Testis Function, Russian Journal of Developmental Biology 52(6) 2021, Fig. 1b, CC BY 4.0; via Wikimedia Commons, cropped to panel b with an English key added by Chalklet AI Labs |
| body-axes-cephalisation | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| body-cavities | figure | OpenStax, Biology 2e (Figure 27 02 05), via Wikimedia Commons - CC BY 4.0; cropped to the three cross-section diagrams (photographs removed), the word 'mollusks' re-lettered 'molluscs' |
| body-surface-respiration | figure | Hickerson (FGBNMS), Xestospongia muta, public domain; Holger Brandl and colleagues, Planaria torva, CC BY 4.0; Donald Hobern, Lumbricus terrestris, CC BY 2.0; via Wikimedia Commons, cropped and labelled by Chalklet |
| body-symmetry | figure | OpenStax, Biology for AP Courses (Figure 33.1.1, animal symmetry), CC BY 4.0 as released before 2026-04-23 |
| bone-lacunae-canaliculi | figure | A. N. and D. McAlpine, Biological Atlas (1880), Plate XXIV, public domain, via Wikimedia Commons |
| bony-fish-anatomy | figure | Dev Jadiya, Wikimedia Commons, CC0 (re-cropped from the full-resolution original to the chart alone) |
| borosilicate-glassware-photo | figure | Skatebiker at English Wikipedia, Schott Duran glassware, public domain, via Wikimedia Commons |
| brain-coronal-section | figure | Rajalakshmi L Nair et al., Wikimedia Commons, CC BY 2.0 |
| brain-sagittal | figure | DataBase Center for Life Science (DBCLS), via Wikimedia Commons - CC BY 4.0 |
| brain-surface-structures | figure | Blausen.com staff (2014). Medical gallery of Blausen Medical 2014. WikiJournal of Medicine 1(2). CC BY 3.0, via Wikimedia Commons; cropped, title removed |
| brain-ventricles | figure | Blausen.com staff (2014). Medical gallery of Blausen Medical 2014. WikiJournal of Medicine 1(2). CC BY 3.0, via Wikimedia Commons |
| brass-ingot | figure | Danielle Wootton, Portable Antiquities Scheme, CC BY 2.0, via Wikimedia Commons |
| brassica-oleracea-varieties | figure | Jazze7 (North India street vegetable seller), CC0, via Wikimedia Commons; cropped and labelled by Chalklet |
| brassicaceae-radish-siliqua | figure | Pearson Scott Foresman (radish, public domain); Chambers Twentieth Century Dictionary 1908 (siliqua, public domain); via Wikimedia Commons, labelled by Chalklet |
| bridge-expansion-joint | figure | Retaildesigner, Wikimedia Commons, public domain |
| bronchiole-asthma | figure | Baedr-9439, via Wikimedia Commons - CC0 |
| brown-algae-colour-flagella | figure | W.carter, Bladder wrack in Samstad harbor, CC0; Olivier Barbaroux / Ifremer, Laminaria digitata, CC BY 4.0; cells drawn by Chalklet AI Labs |
| brown-algae-sargassum-laminaria | figure | BrickLightning (Sargassum, CC0) and Stemonitis (Laminaria, CC BY 2.5); via Wikimedia Commons, set side by side and labelled by Chalklet AI Labs |
| bryophyte-sporophyte | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| bt-toxin-crystals | figure | Jim Buckman, Wikimedia Commons, public domain |
| burning-wick | figure | Rhetos, Wikimedia Commons, CC0 |
| bus-photo | figure | Zhunghua 8832, HK bus interior March 2024, CC0, via Wikimedia Commons |
| c3-c4-habitats | figure | Teknad (cereal field near Mantes-la-Jolie, CC0); KoheiU (sugarcane field at Chau Khe, CC0); via Wikimedia Commons, cropped and labelled by Chalklet |
| c3-c4-leaf-sections | figure | OpenStax, Biology 2e (Figure 30.4.6 a), CC BY 4.0; Kelvinsong, Zea mays leaf Kranz anatomy (CC BY 3.0) with labels by Chalklet; via Wikimedia Commons, composed by Chalklet |
| caesium-chloride-lattice | figure | Benjah-bmm27, Wikimedia Commons, public domain |
| calcium-carbonate-forms | figure | Composite: limestone by Szilas, public domain; chalk by James St. John, CC BY 2.0; Carrara marble quarry by Reiner Flassig, public domain; scallop shell by George Chernilevsky, public domain; coral reef by Jim E. Maragos, US Fish and Wildlife Service, public domain; via Wikimedia Commons |
| callus-tissue-culture | figure | Bstlee (carrot tissue in glass), public domain, via Wikimedia Commons; cropped and labelled by Chalklet |
| calyx-corolla-aestivation | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| cambium-ring-heartwood | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| candle | figure | Rolf Schweizer Fotografie, Pourquoi. Lit candle., CC BY 2.0, via Wikimedia Commons |
| candle-luminous-flame | figure | Forrestjunky, derivative of Candle-flame-and-reflection.jpg, public domain, via Wikimedia Commons |
| cannabis-inflorescence | figure | Alex Abair, Cannabis sativa (iNaturalist 8729254), CC BY 4.0, via Wikimedia Commons |
| capillary-bed | figure | OpenStax College, Anatomy and Physiology, CC BY 3.0, via Wikimedia Commons |
| capillary-exchange | figure | OpenStax College, Anatomy and Physiology, CC BY 3.0, via Wikimedia Commons |
| capillary-rise-setup | figure | OpenStax, Chemistry, Wikimedia Commons, CC BY 4.0 |
| car-tyre-photo | figure | Antti, Porsche Tire Pressure Gauge, CC BY 2.0, via Wikimedia Commons |
| cardiac-conduction | figure | OpenStax College, Anatomy and Physiology, Wikimedia Commons, CC BY 3.0 |
| cartilage-types | figure | OpenStax, Anatomy and Physiology 2e (Types of Cartilage, section 4.3), CC BY 4.0 as released before 2026-04-23 |
| castor-germinating-glyoxysomes | figure | 5snake5, via Wikimedia Commons - CC0; heading and caption added by Chalklet |
| catalytic-converter-honeycomb-photo | figure | Cyrogigabyte, Catalytic Converter Interior, CC0, via Wikimedia Commons |
| catch-and-crumple-zone | figure | Composite: outfielder catching by HRVdriveblue4449, CC BY 4.0; crashed car by Pete from Liverpool, CC0 (number plate and faces blurred); via Wikimedia Commons |
| cathode-ray-tube | figure | Chris Burks Chetvorno, Wikimedia Commons, public domain |
| cattle-egret-grazing | figure | Kingshuk Mondal, CC BY 4.0, via Wikimedia Commons; cropped and labelled by Chalklet |
| cave-art-lascaux | figure | HTO, Wikimedia Commons, public domain |
| cave-stalactites | figure | Pseudopanax, Wikimedia Commons, public domain |
| cavendish-torsion-balance | figure | Chris Burks, Wikimedia Commons, public domain (white ground added) |
| cell-wall-architecture | figure | Sleytr UB, Schuster B, Egelseer EM and Pum D (2014) FEMS Microbiology Reviews 38:823-864, via Wikimedia Commons - CC BY 3.0; modified 2026-10-15: legend spellings 'peptido glycan' and 'lipo protein' joined to 'peptidoglycan' and 'lipoprotein' |
| cell-wall-plasmodesmata | figure | Jackacon and Smartse, Wikimedia Commons, public domain |
| cell-wall-primary-secondary | figure | Christophe Loix, Michiel Huybrechts, Jaco Vangronsveld and colleagues (2017), Structure and composition of the primary and secondary cell wall of plants, CC BY 4.0, via Wikimedia Commons |
| cellular-respiration-locations | figure | OpenStax, Anatomy and Physiology (Figure 24.3, Cellular Respiration), CC BY 4.0 as released before 2026-04-23 |
| centriole-hub | figure | Blausen.com staff (2014). Medical gallery of Blausen Medical 2014. WikiJournal of Medicine 1(2). CC BY 3.0, via Wikimedia Commons; cropped, cell inset removed |
| centrosome-centrioles | figure | Kelvinsong, Wikimedia Commons, CC BY 3.0 |
| cerebral-cortex-areas | figure | BruceBlaus, Wikimedia Commons, CC BY 3.0 |
| charged-ruler-paper-photo | figure | Phi6guy, static electricity demonstration (video still), CC BY 4.0, via Wikimedia Commons; caption added |
| chemiosmosis-atp-synthase | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| chlamydomonas-to-kelp | figure | Composite: Chlamydomonas SEM, Dartmouth Electron Microscope Facility, public domain; giant kelp holdfast, Claire Fackler (CINMS, NOAA), public domain; via Wikimedia Commons |
| chlorella-spirulina | figure | Martinus Willem Beijerinck 1890 (Chlorella vulgaris, public domain) and Perdita (Spirulina tablets, public domain); via Wikimedia Commons, set side by side and labelled by Chalklet AI Labs |
| chloroplast | figure | Kelvinsong, via Wikimedia Commons - CC0 |
| chloroplast-labelled | figure | Kelvinsong, via Wikimedia Commons (Chloroplast_II.svg) - CC BY 3.0; modified 2026-10-15: title banner and light-reaction inset removed, the label 'Stromal thylakoids (lamellae or frets)' replaced by NCERT's term 'Stroma lamellae' |
| chloroplast-reaction-sites | figure | OpenStax, Biology 2e (Figure 8.1.6, chloroplast), CC BY 4.0 as released before 2026-04-23 |
| choanocyte | figure | Clark MA, Choi J and Douglas M, OpenStax Biology 2e, CC BY 4.0, via Wikimedia Commons |
| chordate-body-plan | figure | public domain/cc0 diagram (General chordate morphology.svg), via Wikimedia Commons |
| chromatin-charge-heterochromatin | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| chromatin-organisation | figure | DataBase Center for Life Science, DBCLS, CC BY 4.0 |
| chromosomal-aberrations-cancer | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| cicada-ecdysis | figure | KellyC.5366 (Cicada Emerging from Shell - 6 of 8), CC BY 4.0, via Wikimedia Commons |
| cilia-vs-flagellum | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| ciliated-epithelium-sem | figure | Charles Daghlian (Dartmouth Electron Microscope Facility), Bronchiolar epithelium 3 - SEM, public domain, via Wikimedia Commons, cropped and labelled by Chalklet |
| city-smog | figure | Syced, Wikimedia Commons, CC0 |
| clay-and-bauxite-photo | figure | James St. John, Hard kaolinite (Huntley Kaolinite Mine, California), CC BY 2.0; Darla Sondrol, Bauxite (GeoDIL 156), CC0; via Wikimedia Commons, composited by Chalklet |
| cleavage-blastocyst | figure | OpenStax College, Anatomy and Physiology, CC BY 3.0, via Wikimedia Commons |
| closed-open-circulation | figure | OpenStax, Biology 2e, CC BY 4.0, via Wikimedia Commons |
| coca-plant-leaves | figure | Mike Kruger, Erythroxylum coca with fruits and leaves, CC BY 4.0, via Wikimedia Commons |
| column-chromatography | figure | quantockgoblin, Wikimedia Commons, public domain |
| comet-components | figure | NASA, public domain, via Wikimedia Commons |
| commensalism-barnacle-clownfish | figure | Joe McKenna (whale barnacles, CC BY 2.0) and Janderk (common clownfish, public domain); via Wikimedia Commons, labelled by Chalklet AI Labs |
| comparative-embryos | figure | Ernst Haeckel, lithograph by J. G. Bach of Leipzig, from Anthropogenie (1874), via Wikimedia Commons - public domain |
| competitive-inhibition | figure | TimVickers (after Jerry Crimson Mann), Wikimedia Commons, public domain |
| compound-eye-ommatidia | figure | Opoterser, Wikimedia Commons, CC BY 3.0 |
| conifer-life-cycle | figure | OpenStax, Concepts of Biology (Figure 14.3.1, conifer life cycle), CC BY 4.0 as released before 2026-04-23 |
| connective-tissue-cells-matrix | figure | OpenStax College, Anatomy and Physiology, Connective Tissue Proper, CC BY 4.0 as released before 2026-04-23; drawing panel only, ground-substance label and key added by Chalklet AI Labs |
| coralloid-mycorrhiza | figure | OpenStax, Biology 2e (Figure 24.3.4a, after Randy Molina USDA), CC BY 4.0; with a Cycas root panel drawn for this project by Chalklet |
| cork-cambium | figure | Berkshire Community College Bioscience Image Library, Woody Dicot Stem Cork Cambium and Cortex in One Year Sambucus, CC0; via Wikimedia Commons, labelled by Chalklet AI Labs |
| cork-stopper | figure | TheBernFil, Wikimedia Commons, public domain |
| coronary-arteries | figure | Blausen.com staff (2014). Medical gallery of Blausen Medical 2014. WikiJournal of Medicine 1(2). CC BY 3.0, via Wikimedia Commons; title cropped |
| coronary-artery-plaque | figure | Blausen.com staff (2014). Medical gallery of Blausen Medical 2014. WikiJournal of Medicine 1(2). CC BY 3.0, via Wikimedia Commons; cropped to the cut-open artery, heart inset and magnifier ring removed |
| corpora-quadrigemina | figure | Henry Gray, Anatomy of the Human Body (1918), fig. 719, public domain, via Wikimedia Commons; ring and labels by Chalklet AI Labs |
| cortical-reaction-block | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) on Mariana Ruiz Villarreal's public-domain 'Acrosome reaction diagram' - owned |
| corticospinal-decussation | figure | OpenStax, Anatomy and Physiology (Figure 14.26, Corticospinal Pathway), CC BY 4.0 as released before 2026-04-23 |
| countercurrent-multiplier | figure | OpenStax College, Anatomy and Physiology Fig. 25.13, via Wikimedia Commons, CC BY 3.0 |
| crayfish-green-gland | figure | Willy Kuekenthal, Leitfaden fuer das Zoologische Praktikum (Astacus, Fig. 122), CC0, via Wikimedia Commons; German key words re-lettered in English and figure caption cropped by Chalklet |
| cretinism-myxoedema | figure | Composite: cretinism with goitre, W.S. Bainbridge, public domain; myxoedema, watercolour by Thomas Godart, Wellcome Collection, CC BY 4.0; via Wikimedia Commons |
| cristae-vs-thylakoids | figure | Composite: mitochondrion by Mariana Ruiz Villarreal (LadyofHats), public domain; chloroplast by Kelvinsong, CC BY 3.0 (both as registered, with their NCERT respellings); via Wikimedia Commons |
| crossing-over | figure | Science Artist, via Wikimedia Commons - CC0 |
| cryptic-colouration-monarch | figure | Composite: lizard by Rafa acioly, CC0; monarch butterfly by Korall, CC BY 3.0; via Wikimedia Commons |
| csf-choroid-plexus | figure | OpenStax College, Anatomy and Physiology, Cerebrospinal Fluid Circulation, CC BY 4.0 as released before 2026-04-23 |
| ctenophore-features | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| cuckoo-eggs-host-clutch | figure | Simon Speed, Bedford Museum, Wikimedia Commons, public domain |
| curd-setting | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| cuticle-leaf-root | figure | Berkshire Community College Bioscience Image Library, Nerium leaf epidermis and cuticle and Lilium root epidermis with root hair, CC0, via Wikimedia Commons, cropped and labelled by Chalklet |
| cyanobacteria | figure | via Wikimedia Commons - CC0 |
| cyanobacteria-bloom | figure | T. Joyce, NOAA Great Lakes Environmental Research Laboratory (2011), public domain, via Wikimedia Commons; captions by Chalklet AI Labs |
| cyanobacteria-oscillatoria-azolla | figure | Dionaea-muscipula-meow (Oscillatoria, CC0) and Jeffrey Lee (Azolla filiculoides, CC BY 4.0); via Wikimedia Commons, set side by side and labelled by Chalklet AI Labs |
| cyanosis-nails-lips | figure | Joshi et al., Cureus 2024, bilateral pulmonary arteriovenous malformations, fig. 1, CC BY 4.0, via Europe PMC; caption added |
| cycas-dioecious | figure | Cycas micronesica (fadang) male cone and female cone photographs, University of Guam, CC0; via Wikimedia Commons, set side by side and labelled by Chalklet AI Labs |
| cyclic-photophosphorylation | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| cyclone-and-bag-filter | figure | Composite: cyclone separator by Sebastian Enz, public domain; bag filter by Tetris L, public domain; via Wikimedia Commons |
| cytokinesis-animal-plant | figure | OpenStax, Biology 2e (Figure 10 02 04), via Wikimedia Commons - CC BY 4.0 |
| darwin-finches-beaks | figure | John Gould 1845, Darwin finches, public domain; via Wikimedia Commons, labelled by Chalklet AI Labs |
| darwin-galapagos | figure | George Richmond (portrait of Charles Darwin, 1840, public domain); Wellcome Collection, General chart of the principal tracks of HMS Beagle 1831-6 (CC BY 4.0); via Wikimedia Commons, cropped and labelled by Chalklet |
| darwins-finches-gould | figure | John Gould, from Darwin's Journal of Researches (1845), public domain |
| deep-sea-anglerfish | figure | August Brauer, 1906 (Valdivia expedition), Melanocetus johnsonii, public domain; via Wikimedia Commons, labelled by Chalklet AI Labs |
| desert-lizard-basking | figure | Raja bandi, CC BY 4.0, via Wikimedia Commons; labelled by Chalklet |
| detritus-earthworm | figure | Composite: leaf litter, US Forest Service, public domain; earthworm by GTSPACE, CC0; via Wikimedia Commons |
| diamond-lattice | figure | Pieter Kuiper, Wikimedia Commons, public domain |
| diatom-frustule | figure | Mary Ann Tiffany, San Diego State University (panel A of Diatoms.png), CC BY 2.5, via Wikimedia Commons |
| diatomaceous-earth | figure | SprocketRocket, Diatomaceous Earth, CC0; via Wikimedia Commons, set side by side and labelled by Chalklet AI Labs |
| dicot-embryo-stages | figure | OpenStax, Biology 2e (Figure 32 02 08abcd), via Wikimedia Commons - CC BY 4.0; the label 'Short meristem' re-lettered 'Shoot meristem' |
| dicot-monocot-root-ts | figure | OpenStax, Biology 2e, CC BY 4.0, via Wikimedia Commons |
| digestive-system | figure | Servier Medical Art, via Bioicons - CC BY 3.0 |
| digestive-system-overview | figure | Blausen.com staff (2014). Medical gallery of Blausen Medical 2014. WikiJournal of Medicine 1(2). CC BY 3.0, via Wikimedia Commons; cropped, title removed; label Esophagus rewritten Oesophagus |
| dihybrid-cross-peas | figure | OpenStax, Biology 2e (Figure 12.3.2), CC BY 4.0, via Wikimedia Commons |
| dinoflagellate | figure | OpenStax, Biology 2e (Figure 23 03 04), via Wikimedia Commons - CC BY 4.0 |
| diode-cathode-band | figure | Zxelt, Wikimedia Commons, CC0 |
| diploblast-triploblast | figure | OpenStax, Biology 2e (Figure 27 02 04), via Wikimedia Commons - CC BY 4.0 |
| dna-double-helix | figure | Thomas Shafee, via Wikimedia Commons - CC BY 4.0, modified 2026-09-01: root fill #E6E6E6 added so ink that set no fill of its own renders light on the dark board - geometry, glyphs and the base colours unchanged |
| dna-precipitate-ethanol | figure | Sheila Richards, Wikimedia Commons, CC BY 4.0 |
| dogfish-vertebrae-notochord | figure | T. J. Parker and W. A. Haswell, A Text-book of Zoology vol. 2 (1910), fig. 812, public domain, via Internet Archive |
| dosa-idli-batter | figure | Pamri, Dosa batter2, public domain, via Wikimedia Commons, labelled by Chalklet |
| double-fertilisation | figure | OpenStax, Biology 2e (Figure 32 02 07), via Wikimedia Commons - CC BY 4.0; 'fertilizes' re-lettered 'fertilises' twice |
| dough-rising | figure | afsdfgasdf (Rising dough overflowing its container), CC BY 2.0, via Wikimedia Commons |
| down-syndrome-features | figure | Composite: Sydney S. Gellis and Murray Feingold, Down syndrome 4 and 6, public domain; Vincenwoo, single transverse palmar crease, CC0; via Wikimedia Commons |
| down-syndrome-stature | figure | Barts Health NHS Trust Archives / Wellcome Collection (L0067016), CC BY 4.0, via Wikimedia Commons; cropped, labelled |
| dragonfly | figure | Tero Keski-Valkama, Wikimedia Commons, CC0 |
| drosophila-fly | figure | Alexis (Drosophila melanogaster 53362116), CC BY 4.0, via Wikimedia Commons |
| drupe-pericarp-layers | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| dry-cell | figure | Tympanus, derivative by Tucvbif and Lead holder, Wikimedia Commons, public domain |
| ear-anatomy | figure | Blausen.com staff (2014). Medical gallery of Blausen Medical 2014. WikiJournal of Medicine 1(2). CC BY 3.0, via Wikimedia Commons; cropped, title removed; label Elastic cartilages and its leader lines removed; External acoustic meatus relabelled External auditory meatus; Auditory tube relabelled Eustachian tube |
| early-earth | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| earthworm | figure | Encyclopaedia Britannica 1911 (Chaetopoda Fig. 10 - Diagrams of various Earthworms, to illustrate external characters), via Wikimedia Commons - public domain |
| echinoderm-larva-and-adult | figure | Ernst Haeckel, Kunstformen der Natur (1904) Tafel 40, Figs. 3 and 1, public domain, via Wikimedia Commons; cropped, plate numbers removed and captions added by Chalklet |
| ectoparasites-louse-cuscuta | figure | Korinna (head louse, CC BY 4.0) and Robert Flogaus-Faust (Cuscuta europaea, CC BY 4.0); via Wikimedia Commons, labelled by Chalklet AI Labs |
| electrolytic-capacitor | figure | Inductiveload, Wikimedia Commons, public domain (white ground added) |
| electrolytic-cell | figure | Torsten Henning, Wikimedia Commons, public domain |
| electronic-components-and-symbols | figure | Evan-Amos (LED, resistor, ceramic capacitor photographs, public domain) and Zxelt (diode photograph, CC0), via Wikimedia Commons; circuit symbols and labels drawn by Chalklet |
| electrostatic-precipitator-plan | figure | Meroth (drawing) and wdwd (SVG), CC BY 3.0, via Wikimedia Commons; German labels translated into English and a white ground added |
| elephantiasis | figure | CDC Public Health Image Library (PHIL 373), via Wikimedia Commons - public domain |
| emasculation-and-bagging | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| embryo-axis-micropylar | figure | OpenStax College, Biology 2e, Figures 32.2.8 (a-b) and 32.2.9 (bean seed), CC BY 4.0 as released before 2026-04-23; set side by side with end labels and a key by Chalklet AI Labs |
| embryo-sac | figure | Tameeria, via Wikimedia Commons - public domain |
| embryos-romanes | figure | George John Romanes, Darwin and After Darwin (1892), after Haeckel; public domain, via Wikimedia Commons |
| emphysema-alveoli | figure | Blausen.com staff (2014). Medical gallery of Blausen Medical 2014. WikiJournal of Medicine 1(2). CC BY 3.0, via Wikimedia Commons; cropped to the two alveoli insets, body figure and watermark removed |
| emphysema-fibrosis | figure | Blausen.com staff (2014), Medical gallery of Blausen Medical 2014, WikiJournal of Medicine 1(2), CC BY 3.0, via Wikimedia Commons (emphysema plate, cropped); membrane and airway panels drawn by Chalklet AI Labs |
| endocrine-glands | figure | OpenStax College, Anatomy and Physiology, via Wikimedia Commons - CC BY 3.0 |
| endocrine-system-overview | figure | Blausen.com staff (2014). Medical gallery of Blausen Medical 2014. WikiJournal of Medicine 1(2). CC BY 3.0, via Wikimedia Commons; unmodified |
| endomembrane-system | figure | Mariana Ruiz LadyofHats, Wikimedia Commons, public domain |
| endomembrane-traffic | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| endoplasmic-reticulum | figure | Servier Medical Art, via Bioicons - CC BY 3.0 |
| endosperm-free-nuclear-to-cellular | figure | Wei et al., Frontiers in Plant Science 16:1640284 (2025), fig. 1 panels A-C, CC BY 4.0, via Europe PMC; caption added |
| entamoeba-cyst | figure | Yasser from Cairo, Wikimedia Commons, CC BY 2.0 |
| enzyme-active-site | figure | TimVickers, vectorised by Fvasconcellos, Wikimedia Commons, public domain |
| enzyme-saturation-sites | figure | Chalklet AI Labs, drawn for this project (figures/pic2_drawings.py) - owned |
| epiglottis-swallowing | figure | OpenStax College, Anatomy and Physiology, Deglutition figure, CC BY 4.0 as released before 2026-04-23; epiglottis labels added by Chalklet AI Labs |
| epiphyte-orchid-branch | figure | Malcolm Manners, CC BY 2.0, via Wikimedia Commons; labelled by Chalklet |
| epithelium-classification | figure | Blausen.com staff (2014). Medical gallery of Blausen Medical 2014. WikiJournal of Medicine 1(2). CC BY 3.0, via Wikimedia Commons; title removed |
| er-rough-smooth | figure | Blausen.com staff (2014). Medical gallery of Blausen Medical 2014. WikiJournal of Medicine 1(2). CC BY 3.0, via Wikimedia Commons; cropped to the endoplasmic reticulum, inset cell removed |
| erythrocyte | figure | Servier Medical Art, via Bioicons - CC BY 3.0 |
| ethylene-triple-response | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| etiolation-dark-light | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| euglena-cell | figure | Claudio Miklos (Euglena diagram), CC0, via Wikimedia Commons |
| euglena-light-dark | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| evaporative-cooler | figure | Buster2058, Wikimedia Commons, public domain |
| exocytosis | figure | OpenStax, Biology 2e (Figure 05 04 04), via Wikimedia Commons - CC BY 4.0 |
| exophthalmos | figure | CNX OpenStax, Microbiology, CC BY 4.0, via Wikimedia Commons |
| extinct-dodo-quagga | figure | Composite: dodo model by Nosferattus (Carnegie Museum of Natural History), CC0; quagga by Jacques-Laurent Agasse, public domain; via Wikimedia Commons |
| extinct-thylacine-seacow-tigers | figure | Composite via Wikimedia Commons: thylacines (E.J. Keller, Smithsonian), public domain; Steller's sea cow skeleton by Cliff from Arlington, CC BY 2.0; Bali tiger skin (Leiden museum), Javan tiger (F.W. Bond), Caspian tiger, public domain |
| eye-anatomy-overview | figure | Blausen.com staff (2014). Medical gallery of Blausen Medical 2014. WikiJournal of Medicine 1(2). CC BY 3.0, via Wikimedia Commons; cropped, title removed |
| factory-smoke-plume-photo | figure | Harry Schaefer, More smoke is emitted by Union Carbide ferroalloy plant in Alloy (Documerica), public domain (US EPA), via Wikimedia Commons |
| false-fruits-apple-strawberry-cashew | figure | Forest and Kim Starr (apple, CC BY 3.0 US); Scott Bauer, USDA (strawberry, public domain); Preetti Sri (cashew, CC0); via Wikimedia Commons, cropped and labelled by Chalklet |
| families-placentation-fruit | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| feather-scale-aerofoil | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| female-reproductive-system | figure | CDC; vectorised by Mysid, via Wikimedia Commons - public domain |
| female-reproductive-system-overview | figure | Blausen.com staff (2014). Medical gallery of Blausen Medical 2014. WikiJournal of Medicine 1(2). CC BY 3.0, via Wikimedia Commons; cropped to the pelvic panel, whole-body inset and title removed |
| fermented-foods | figure | Wrote (fermented herring), Kinchan1 (natto, CC BY 2.0) and DryPot (menma, CC BY 2.5), CC BY 2.0 and 2.5, via Wikimedia Commons |
| fern-antherozoid-swim | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| fern-sorus-indusium | figure | Tgru001, Fern Athyrium leaf and sorus 100x, Wikimedia Commons, CC BY 4.0; frond photo by Oblikerg, CC0; layout and labels by Chalklet AI Labs |
| fern-sporophyte | figure | CNX OpenStax (Biology 2e, Figure 25.4.7 fern life cycle), via Wikimedia Commons - CC BY 4.0; the label 'Sporongia' re-lettered as 'Sporangia' |
| fern-true-organs | figure | Hermann Adolf Koehler, Medizinal-Pflanzen (1887), public domain, via Wikimedia Commons; plate letters re-lettered as English labels by Chalklet |
| fern-vascular-transport | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| fertilisation-corona | figure | Blausen.com staff (2014). Medical gallery of Blausen Medical 2014. WikiJournal of Medicine 1(2). CC BY 3.0, via Wikimedia Commons; body outline and American-spelt titles masked |
| fibrin-clot-sem | figure | Janice Carr, CDC Public Health Image Library, public domain |
| fig-wasps-in-fig | figure | Alandmanson, Wikimedia Commons, CC BY 4.0 |
| filariasis-microfilariae-vector | figure | CDC DPDx (Wuchereria bancrofti and Brugia malayi microfilariae) and CDC PHIL 17697 by James Gathany (Culex quinquefasciatus), public domain; via Wikimedia Commons, set side by side with captions by Chalklet AI Labs |
| finches-separate-islands | figure | Balon Greyjoy, Galapagos islands hotspot map, CC0; John Gould 1845, Darwin finches, public domain; via Wikimedia Commons, cropped and labelled by Chalklet |
| fish-gills | figure | OpenStax, Biology 2e, CC BY 4.0, via Wikimedia Commons |
| fish-mouth-positions | figure | Chris_huh (shark external anatomy) and Nilheda (Catla catla, caption and credit cropped), public domain, via Wikimedia Commons |
| fish-osmoregulation-gills | figure | OpenStax, Biology 2e (Figure 41.1.2), CC BY 4.0; marine-panel urine and arrow labels re-lettered by Chalklet (urine no more concentrated than blood) |
| fish-scales-cycloid-ctenoid | figure | John Graham Kerr, Encyclopaedia Britannica (1911), public domain |
| fish-tails-homocercal-heterocercal | figure | Robert Chambers, Vestiges of the Natural History of Creation (1844), public domain |
| flame-cell-nephridium | figure | OpenStax, Biology 2e, CC BY 4.0, via Wikimedia Commons |
| flamingo-fish-competition | figure | Kandukuru Nagarjun, Feeding flamingos, CC BY 2.0; Francois-Louis Laporte (Castelnau), Orestias pentlandii, public domain; via Wikimedia Commons, cropped and labelled by Chalklet |
| flatworms-body-and-examples | figure | Servier Medical Art, Fasciola hepatica adult, CC BY; Taenia scolex drawing (Bandwurm-drawing) and CDC PHIL Dr Mae Melvin proglottids, public domain; cross-section and planarian drawn by Chalklet AI Labs |
| flightless-birds | figure | Drcbrothephotographer (ostriches, CC0) and Ian Duffy (emperor penguins, CC BY 2.0), via Wikimedia Commons |
| flippers-penguin-dolphin | figure | Martin Pettitt (Humboldt penguin, CC BY 2.0) and US Navy (dolphin, public domain); via Wikimedia Commons, labelled by Chalklet AI Labs |
| floating-needle | figure | Gabriel, Wikimedia Commons, CC0 |
| floc-bacteria-fungal-mesh | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| floral-diagram-asteraceae | figure | BotaFlo, via Wikimedia Commons - CC0; the letter codes A to E replaced by the part names |
| floral-diagram-brassicaceae | figure | Afanasovich, via Wikimedia Commons - CC BY 4.0 |
| floral-diagram-malvaceae | figure | de:Benutzer:Griensteidl, via Wikimedia Commons - public domain |
| floral-diagram-solanaceae | figure | de:Benutzer:Griensteidl, via Wikimedia Commons - public domain |
| floral-symmetry-planes | figure | Jengod (Brassica juncea, public domain); Forest and Kim Starr (Pisum sativum, CC BY 3.0); PEAK99 (Canna indica, CC BY 3.0); via Wikimedia Commons, cropped, planes drawn and labelled by Chalklet |
| flower-androecium-gynoecium | figure | OpenStax, Biology 2e (Figure 26 03 02), via Wikimedia Commons - CC BY 4.0 |
| flower-structure | figure | Mariana Ruiz (LadyofHats), via Wikimedia Commons - public domain |
| fluorite-lattice | figure | Benjah-bmm27, Wikimedia Commons, public domain |
| folliculogenesis-stages | figure | OpenStax College, Anatomy and Physiology, CC BY 3.0 |
| forced-expiration-abdomen | figure | OpenStax College, Anatomy and Physiology (2316 Inspiration and Expiration), CC BY 3.0, via Wikimedia Commons; expiration panel only, with arrows on the abdominal wall and a caption added by Chalklet |
| forest-clearing-satellite | figure | NASA/GSFC/MITI/ERSDAC/JAROS and U.S./Japan ASTER Science Team, Bolivia satellite deforestation 1986 2001, public domain; via Wikimedia Commons, labelled by Chalklet AI Labs |
| foucault-pendulum-photo | figure | Stephen Rahn, Foucault pendulum in Tellus Science Museum, CC0, via Wikimedia Commons |
| free-nuclear-endosperm | figure | Johnston et al., Genome Biology 2007 8 R204, Fig. 1a and 1f, CC BY 2.0; via Wikimedia Commons, two panels cropped with an English key added by Chalklet AI Labs |
| frog-amplexus-eggs | figure | Nwonwu Uchechukwu P, Wikimedia Commons, CC0 |
| frog-amplexus-nuptial-pad | figure | Vipin Baliga (amplexus, CC BY 2.0) and Wan H, Lyu Z-T, Qi S, Zhao J, Li P-P, Wang Y-Y, ZooKeys 942 (nuptial pad, CC BY 4.0), via Wikimedia Commons |
| frog-bile-duct | figure | S. J. Holmes, The Biology of the Frog (1906), fig. 42 (after Wiedersheim), public domain, via Wikimedia Commons / BHL; key and duct trace by Chalklet AI Labs |
| frog-brain | figure | McAlpine, Archibald N. and Daniel McAlpine, Biological Atlas (Edinburgh: W. & A. K. Johnston, 1880), Plate XXI, via Internet Archive (biologicalatlasg00mcalrich) / Wikimedia Commons - public domain |
| frog-brain-pituitary | figure | Samuel J. Holmes, The Biology of the Frog (1906), Fig. 83 D after Gaupp and Osborn, public domain, via the Biodiversity Heritage Library and Wikimedia Commons; inf and pit written out and the codes keyed by Chalklet |
| frog-buccal-pumping | figure | Samuel J. Holmes, The Biology of the Frog (1906), Fig. 46 after Parker and Parker, public domain, via Biodiversity Heritage Library and Wikimedia Commons; caption and key added |
| frog-circulatory | figure | Gilchrist and Bonde, 'Dissection of the Platana and the Frog' (1919), via Biodiversity Heritage Library / Wikimedia Commons - public domain |
| frog-digestive | figure | Bonde and Gilchrist, 'Dissection of the Platana and the Frog' (1919), via Biodiversity Heritage Library / Wikimedia Commons - public domain |
| frog-endocrine-glands | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py), re-drawn from public-domain plates (see drawn.reference) - owned |
| frog-external | figure | St. George Mivart, 'The Common Frog' (1873), via Biodiversity Heritage Library / Wikimedia Commons - public domain; cropped from the page scan |
| frog-eye | figure | Ren West, Frog eye closeup, CC BY 2.0, via Wikimedia Commons; cropped |
| frog-gut-cloaca-folds | figure | S. J. Holmes, The Biology of the Frog (1907), figs. 38 and 41, public domain, via Internet Archive; captions added |
| frog-heart-chambers | figure | Samuel J. Holmes, The Biology of the Frog (1906), Figs. 72 and 73 (after Parker and Haswell, and Howes), public domain; via Wikimedia Commons from the Biodiversity Heritage Library, set side by side with stream arrows and an English key added by Chalklet AI Labs |
| frog-life-cycle-breathing | figure | James Ritchie, Frog lifecycle (public domain), via Wikimedia Commons; labelled and captioned by Chalklet |
| frog-nervous | figure | Gilchrist and Bonde, 'Dissection of the Platana and the Frog' (1919), via Biodiversity Heritage Library / Wikimedia Commons - public domain |
| frog-nictitating-membrane | figure | Dave Huth, Wikimedia Commons, CC BY 2.0 |
| frog-portal-lymph | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| frog-skin-capillaries-section | figure | Xu, Dai, Zheng et al., Zoological Letters 9:20 (2023), fig. 2F, CC BY 4.0, via Europe PMC; caption added |
| frog-skin-glands-capillaries | figure | Alexander Ecker and George Haslam, The Anatomy of the Frog (1889), figs. 229 and 235, public domain, via Biodiversity Heritage Library and Wikimedia Commons; captions added |
| frog-testis-bidders-canal | figure | Alexander Ecker, The Anatomy of the Frog, tr. George Haslam (1889), Fig. 222 I, public domain, via the Biodiversity Heritage Library and Wikimedia Commons; letter codes replaced by English names from Ecker's legend by Chalklet |
| frog-tongue-flick | figure | Samuel J. Holmes, The Biology of the Frog (1906), Fig. 6 after Wiedersheim, public domain, via Biodiversity Heritage Library and Wikimedia Commons; caption added |
| frog-tympanum-columella | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py), re-drawn from public-domain plates (see drawn.reference) - owned |
| frog-urinogenital | figure | Gilchrist and Bonde, 'Dissection of the Platana and the Frog' (1919), via Biodiversity Heritage Library / Wikimedia Commons - public domain |
| frog-vocal-sac | figure | Clinton and Charles Robertson, Wikimedia Commons, CC BY 2.0 |
| frog-vs-mammal-brain | figure | Composite: frog brain from McAlpine, Biological Atlas (1880), public domain; human brain from Blausen Medical (WikiJournal of Medicine 2014), CC BY 3.0; via Wikimedia Commons |
| frost-split-boulder-photo | figure | UCL Mathematical and Physical Sciences (Bridget Wade), Iceland weathering, CC BY 2.0, via Wikimedia Commons; caption added |
| fruit-types | figure | James St. John, via Wikimedia Commons - CC BY 2.0 |
| fruit-types-dry-fleshy | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| fuel-cell | figure | Mattuci, Wikimedia Commons, CC0 |
| fungal-hyphae-nutrition | figure | Iryna Buchnieva, Champignons with mycelium, CC BY 4.0, via Wikimedia Commons (resized, labels added); with Christopher Johnson, Insects Unlocked, Tortoise Beetle (genus Stolas), CC0; hypha panel drawn by Chalklet AI Labs |
| fungal-vegetative-reproduction | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| galena-cube | figure | Darla Sondrol (GeoDIL 979), Galena, CC0, via Wikimedia Commons |
| galvanic-electrolytic-cell | figure | Rehua, Wikimedia Commons, CC BY 3.0 |
| gametogenesis-comparison | figure | KaterynaVa, Wikimedia Commons, CC0 |
| gel-electrophoresis | figure | Ultrabem (ultrabem.com), Wikimedia Commons, CC0 |
| gemma-protonema | figure | New Student Reference Work (1914), Protonema of a moss, public domain, via Wikimedia Commons (key letter removed); liverwort and gemma panels drawn by Chalklet AI Labs |
| gene-transfer-methods | figure | OpenStax Microbiology (2016), OSC Microbio 12 01 GeneGun, CC BY 4.0, via Wikimedia Commons (panel a, cropped); micro-injection and Agrobacterium panels drawn by Chalklet AI Labs |
| germ-layers-formation | figure | OpenStax College, Anatomy and Physiology, CC BY 3.0 |
| germination-epigeal-hypogeal | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| gibberellin-effects | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| gigantism-dwarfism | figure | Anonymous, A giant and a dwarf, London, 1927, Wellcome Collection, CC BY 4.0, via Wikimedia Commons; a shop sign blanked, caption added |
| glacier-ice | figure | NASA ICE, public domain, via Wikimedia Commons |
| glass-slab-refraction-photo | figure | ajizai, Refraction photo, public domain, via Wikimedia Commons |
| glomerular-filtration-layers | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| gm-cotton-insect-resistance | figure | CSIRO Plant Industry, CSIRO ScienceImage 381, CC BY 3.0, via Wikimedia Commons |
| goitre-photo | figure | OpenStax, Anatomy and Physiology, CC BY 4.0 |
| gold-pan | figure | Nate Cull, CC BY 2.0, via Wikimedia Commons |
| golgi-apparatus | figure | Blausen.com staff (2014). Medical gallery of Blausen Medical 2014. WikiJournal of Medicine 1(2). CC BY 3.0, via Wikimedia Commons; cropped, whole-cell inset and title removed |
| golgi-cis-trans | figure | OpenStax, Biology for AP Courses (Figure 4.4.1, endomembrane system), CC BY 4.0 as released before 2026-04-23 |
| gram-wall-envelope | figure | DataBase Center for Life Science (DBCLS), via BioIcons - CC BY 4.0 |
| grana-sun-shade | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| graphite-layers | figure | Benjah-bmm27, Wikimedia Commons, public domain |
| grass-culm-rhizome | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| grass-embryo-ls | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| grass-spikelet | figure | Alfred (Zirpe), derivative by Enzoklop, Grasbluete numbers, public domain; via Wikimedia Commons, English key added by Chalklet AI Labs |
| gravitropism-root-shoot | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| green-algae-chloroplasts-wall | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| green-algae-spirogyra-volvox | figure | Krishna satya 333 (Spirogyra chloroplast, CC0) and Picturepest (Volvox, CC BY 2.0); via Wikimedia Commons, set side by side and labelled by Chalklet AI Labs |
| griffith-smooth-rough-colonies | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| growth-conditions-seedling | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| growth-outside-inside | figure | Meshari Alawfi, Sand Dunes sa, CC BY 4.0; Roy van Heesbeen, TelophaseIF, public domain; via Wikimedia Commons, cropped and labelled by Chalklet |
| growth-plate-fusion-acromegaly | figure | Composite: OpenStax College, Anatomy and Physiology fig. 6.23 epiphyseal plate and line, CC BY 3.0; skiagram of the hand of a patient with acromegaly, Wellcome Collection, CC BY 4.0; via Wikimedia Commons |
| guard-cells-kidney-dumbbell | figure | Umberto Salvagnin, Maize stomata, CC BY 2.0; stomatal apparatus drawing, public domain; via Wikimedia Commons, labelled by Chalklet |
| gut-incomplete-complete | figure | OpenStax, Biology 2e (Figures 28.2.5 and 28.3.7), CC BY 4.0, via Wikimedia Commons |
| gut-wall-four-tissues | figure | OpenStax College, Anatomy and Physiology, Layers of the Gastrointestinal Tract, CC BY 4.0 as released before 2026-04-23; four-tissue key added by Chalklet AI Labs |
| gymnosperm-female-gametophyte | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| gymnosperm-tracheid-sieve-cell | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| gynoecium-types | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| haemodialysis | figure | National Institute of Diabetes and Digestive and Kidney Diseases, Wikimedia Commons, public domain |
| haemoglobin-four-haems | figure | OpenStax, Biology 2e, CC BY 4.0, via Wikimedia Commons |
| haemoglobin-vs-myoglobin | figure | OpenStax, Biology 2e Figure 39.4.1 (haemoglobin), CC BY 4.0; AzaToth, Myoglobin, public domain; via Wikimedia Commons, cropped and labelled by Chalklet |
| haemophilus-colonies | figure | CDC / Dr. W.A. Clark, Public Health Image Library, public domain |
| halite-rock-salt | figure | Aram Dulyan, Wikimedia Commons, public domain |
| hand-bones | figure | Blausen.com staff (2014). Medical gallery of Blausen Medical 2014. WikiJournal of Medicine 1(2). CC BY 3.0, via Wikimedia Commons; cropped, title removed |
| hazardous-waste-drums-photo | figure | John Messina, U.S. EPA Documerica, 1973, public domain; via U.S. National Archives and Wikimedia Commons |
| heads-hetero-homogamous | figure | H. Zell (Helianthus annuus, CC BY 3.0); Cbaile19 (Taraxacum officinale, CC0); via Wikimedia Commons, cropped and labelled by Chalklet |
| heart-attack | figure | Blausen.com staff (2014). Medical gallery of Blausen Medical 2014. WikiJournal of Medicine 1(2). CC BY 3.0, via Wikimedia Commons; cropped, title removed |
| heart-failure-congestion-xray | figure | Mikael Haggstrom, chest radiograph with signs of congestive heart failure (annotated), CC0, via Wikimedia Commons |
| hemichordate-body-plan | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| hepatic-portal-system | figure | OpenStax College, Anatomy and Physiology, CC BY 3.0 |
| herbarium-sheet | figure | The Trustees of the Royal Botanic Gardens Kew (specimen K000832752), CC BY 4.0, via Wikimedia Commons |
| herschel-infrared-experiment | figure | William Herschel, Philosophical Transactions (1800), public domain, via Wikimedia Commons |
| hershey-chase | figure | OpenStax, Biology 2e (Figure 14 01 03), via Wikimedia Commons - CC BY 4.0; cropped to the diagram above the numbered step captions, 'labeled' re-lettered 'labelled' in both labels |
| hertz-spark-experiment | figure | Illustration from Raymond Francis Yates (early 20th century), public domain, via Wikimedia Commons |
| heterocyst | figure | Rikkinen J (2013) Molecular studies on cyanobacterial diversity in lichen symbioses, MycoKeys 6: 3-32, Fig. 2 B and E, CC BY 3.0, via Wikimedia Commons (cropped, labels added); filament panel drawn by Chalklet AI Labs |
| heterophylly-juvenile-mature | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| heterophylly-water-buttercup | figure | Otto Wilhelm Thomé, Flora von Deutschland (1885), public domain, via Wikimedia Commons |
| heterospory | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| hip-bone-lateral | figure | OpenStax College, Anatomy and Physiology, CC BY 3.0 |
| hiv-virion | figure | NIH NIAID (National Institutes of Health), Wikimedia Commons, public domain |
| holoenzyme-cofactor | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| hominid-ancestors | figure | OpenStax Biology 2e Figures 29.7.5 and 29.7.4 a (Lucy skeleton and Australopithecus afarensis skull, CC BY 4.0); José-Manuel Benito Álvarez (Homo habilis KNM-ER 1813, public domain, via Wikimedia Commons); cropped and labelled by Chalklet |
| hominid-fossil-sites | figure | Central Intelligence Agency, The World Factbook (Political Africa), public domain, via Wikimedia Commons; sites marked and labelled by Chalklet |
| homologous-forelimbs | figure | Волков Владислав Петрович (Vladlen666); derivative by Angelito7, via Wikimedia Commons - CC0; English captions translated from the German fallback 2026-09-01 |
| hooke-cork-cells | figure | Robert Hooke, Micrographia (1665), Schem. XI Fig. 1, public domain |
| hookworm-buccal-teeth | figure | CDC Public Health Image Library (Dr. Melvin), via Wikimedia Commons - public domain; labels and caption by Chalklet |
| hose-and-gorge-photo | figure | Composite: Benoit Prieur, jet d'eau, CC0; Sids1, The Huka Falls, CC BY 2.0; via Wikimedia Commons; captions added |
| housefly | figure | USDA, Wikimedia Commons, CC BY 2.0 |
| hubble-orbit-photo | figure | NASA, Hubble Space Telescope in orbit, public domain, via Wikimedia Commons |
| human-heart-section | figure | Blausen.com staff (2014). Medical gallery of Blausen Medical 2014. WikiJournal of Medicine 1(2). CC BY 3.0, via Wikimedia Commons; cropped, title removed; label Conus arteriosis removed, Trabeculae carnae respelt carneae |
| human-skeleton | figure | OpenStax Anatomy and Physiology, Wikimedia Commons, CC BY 4.0 |
| human-teeth-types | figure | OpenStax College, Anatomy and Physiology, CC BY 3.0 |
| hydra | figure | Encyclopaedia Britannica 1911 (Polyp; Hydromedusae - Portion of the body-wall of Hydra), via Wikimedia Commons - public domain |
| hydra-body-layers | figure | A. N. and D. McAlpine, Biological Atlas (1880), Plate X, public domain, via Wikimedia Commons |
| hydra-prey-and-somersault | figure | Internet Archive Book Images, In Brook and Bayou (1897), no known copyright restrictions; and Pierre Lyonnet for Abraham Trembley, Memoires pour servir a l'histoire d'un genre de polypes (1744), Pl. 3 Figs. 5-9, public domain; both via Wikimedia Commons, captions added by Chalklet |
| hydro-generators-photo | figure | Rsparks3, Electric Generators at the Bonneville Lock and Dam, CC0, via Wikimedia Commons |
| hyoid-bone | figure | OpenStax College, Anatomy and Physiology, Hyoid Bone, CC BY 4.0 as released before 2026-04-23; key added by Chalklet AI Labs |
| hyphae-septate-aseptate | figure | OpenStax, Biology 2e (Figure 24.1.4), CC BY 4.0, via Wikimedia Commons |
| hypophyseal-portal-system | figure | OpenStax College, Anatomy and Physiology, CC BY 3.0 |
| hypothalamus-pituitary | figure | OpenStax College, Anatomy and Physiology, CC BY 3.0 |
| icsi-micro-injection | figure | Blausen.com staff (2014). Medical gallery of Blausen Medical 2014. WikiJournal of Medicine 1(2). CC BY 3.0, via Wikimedia Commons; cropped to the injection inset |
| implantation | figure | OpenStax College, Anatomy and Physiology, CC BY 3.0, via Wikimedia Commons |
| incandescent-filament-lamp-photo | figure | Tony Webster, Edison Lightbulb - Antique Filament Light Bulb, CC BY 2.0, via Wikimedia Commons |
| indian-brick-kiln-chimney-photo | figure | Nico Crisafulli, Brick factory, CC BY 2.0, via Wikimedia Commons |
| industrial-melanism-trunks | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| inflorescence-schemas | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| inflorescence-types | figure | Public domain SVG (raceme panel) and de:Benutzer:Griensteidl after Strasburger (cymose panel), via Wikimedia Commons - public domain |
| insect-tracheal-system | figure | OpenStax, Biology 2e, CC BY 4.0, via Wikimedia Commons |
| insect-trap-leaves | figure | NepGrower (Nepenthes rafflesiana, CC BY 2.5) and ImagePerson (Dionaea muscipula, Zagreb Botanical Garden, CC BY 4.0); via Wikimedia Commons, cropped, set side by side and labelled by Chalklet AI Labs |
| inspiration-expiration | figure | OpenStax College, Anatomy and Physiology, CC BY 3.0 |
| intercostals-expiration | figure | OpenStax, Anatomy and Physiology 2e (1114 Thorax), CC BY 4.0 as released before 2026-04-23; heading and caption added by Chalklet |
| intervertebral-disc | figure | OpenStax College, Anatomy and Physiology (Figure 9.6), CC BY 3.0, via Wikimedia Commons |
| intestinal-villi | figure | OpenStax College, Anatomy and Physiology, CC BY 3.0 |
| intestinal-villus | figure | NIH NIAID BioArt 573, Intestinal Villus, CC BY 4.0, via Wikimedia Commons; cropped |
| intrauterine-insemination | figure | Blausen.com staff (2014). Medical gallery of Blausen Medical 2014. WikiJournal of Medicine 1(2). CC BY 3.0, via Wikimedia Commons; cropped to the two insets, body figure removed |
| islets-of-langerhans | figure | OpenStax College, Anatomy and Physiology, Wikimedia Commons, CC BY 3.0 |
| iud-types | figure | Mikael Haggstrom (copper T IUD, CC0); Aung (Multiload Cu-250) and Hic et nunc (Mirena), public domain, via Wikimedia Commons |
| joint-between-bones | figure | OpenStax, Biology 2e (Figure 38.3.3), CC BY 4.0, via Wikimedia Commons |
| kangaroo-rat-desert | figure | Kangaroo rat photograph, public domain; via Wikimedia Commons, labelled by Chalklet AI Labs |
| karyotype-trisomy21 | figure | Courtesy of the National Human Genome Research Institute (Talking Glossary of Genetics, trisomy 21 illustration), via Wikimedia Commons - public domain (PD-USGov-HHS-NIH) |
| kelp-holdfast | figure | Claire Fackler, CINMS, NOAA, public domain |
| kidney-section | figure | Blausen.com staff (2014). Medical gallery of Blausen Medical 2014. WikiJournal of Medicine 1(2). CC BY 3.0, via Wikimedia Commons; cropped to the kidney section, inset body figure removed |
| klinefelter-features | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py), re-drawn from OpenStax Anatomy and Physiology (CC BY 4.0, CC BY 3.0) - owned |
| klinefelter-gynaecomastia | figure | Wu et al., Frontiers in Endocrinology 2025, case report: diabetic ketoacidosis in a patient with Klinefelter syndrome, fig. 2a, CC BY 4.0, via Europe PMC; cropped, caption added |
| knee-front | figure | Blausen.com staff (2014). Medical gallery of Blausen Medical 2014. WikiJournal of Medicine 1(2). CC BY 3.0, via Wikimedia Commons; cropped, leg inset removed |
| knee-joint-ligaments | figure | OpenStax College, Anatomy and Physiology, CC BY 3.0 |
| knee-side | figure | Blausen.com staff (2014). Medical gallery of Blausen Medical 2014. WikiJournal of Medicine 1(2). CC BY 3.0, via Wikimedia Commons; unmodified |
| koel-brood-parasite | figure | Hari K Patibanda, Asian Koel (Cuckoo), CC BY 2.0; via Wikimedia Commons, labelled by Chalklet AI Labs |
| kok-cycle-manganese | figure | Yikrazuul, via Wikimedia Commons - public domain |
| kranz-c4 | figure | Kelvinsong, Zea mays leaf Kranz anatomy 1 200x, CC BY 3.0, via Wikimedia Commons (cropped, ring outlined, labels added); two-cell pathway panel drawn by Chalklet AI Labs |
| ladybird-eating-aphids | figure | David S. Ferry III, Wikimedia Commons, CC0 |
| lake | figure | Mt. Hood Territory (Oregon tourism), Mount Hood reflected in Mirror Lake, Oregon, public domain, via Wikimedia Commons |
| lamprey-feeding-gill-pores | figure | Great Lakes Fishery Commission (sea lampreys on a lake trout, public domain) and Steven Joyner (Petromyzon marinus 33027216, CC BY 4.0), via Wikimedia Commons |
| lamprey-mouth | figure | U.S. Fish and Wildlife Service, via Wikimedia Commons - public domain |
| laser-beam-photo | figure | Telementor, HeNe594nm, CC BY 4.0, via Wikimedia Commons |
| lateral-root-origin | figure | Berkshire Community College Bioscience Image Library, Lateral Root Origin, CC0; via Wikimedia Commons, labelled by Chalklet AI Labs |
| lattice-radio-mast | figure | Trounce, Wikimedia Commons, CC BY 3.0 |
| lead-storage-cell | figure | OpenStax, Chemistry, Wikimedia Commons, CC BY 4.0 |
| leaf-base-sheath-pulvinus | figure | Blokenearexeter (ligule of crested dogstail, public domain); A. B. Rendle, Encyclopaedia Britannica 1911 Leaf fig. 20 (Mimosa pudica, public domain); via Wikimedia Commons, letters re-lettered as English labels by Chalklet |
| leaf-parts-stipules | figure | OpenStax, Biology 2e (Figure 30.4.1), CC BY 4.0; with Alex Abair (Rosa multiflora stipules), CC BY 4.0, via Wikimedia Commons, cropped and labelled by Chalklet |
| leaf-section-air-spaces | figure | OpenStax, Biology 2e (Figure 30.4.6), CC BY 4.0, via Wikimedia Commons |
| leaf-section-layers | figure | OpenStax, Biology 2e (Figure 30.4.3, leaf cross section), CC BY 4.0 as released before 2026-04-23 |
| leaf-structure | figure | User:Kontos after Pearson Scott Foresman (leaf parts panel, public domain) and Agnieszka Kwiecien / Nova (venation panel, CC BY 3.0), via Wikimedia Commons |
| leaf-ts | figure | Encyclopaedia Britannica 1911 (Plants - transverse sections of leaves), via Wikimedia Commons - public domain |
| leaf-types | figure | OpenStax, Biology 2e (Figure 30 04 03), via Wikimedia Commons - CC BY 4.0 |
| leaf-vein-xylem-up | figure | OpenStax, Biology for AP Courses (Figure 8.2.13), CC BY 4.0; numbered key replaced by English labels by Chalklet |
| leaf-venation | figure | OpenStax, Biology 2e (Figure 30 04 02abc), via Wikimedia Commons - CC BY 4.0; the panel letters (a), (b) and (c) masked |
| led-light-bulbs-photo | figure | Geoffrey.landis at English Wikipedia, LED bulbs, CC BY 3.0, via Wikimedia Commons |
| led-structure | figure | Inductiveload, Wikimedia Commons, public domain (white ground added) |
| lenticel | figure | bccoer (Berkshire Community College Bioscience Image Library), via Flickr and Wikimedia Commons - CC0 |
| leydig-testosterone-regulation | figure | OpenStax College, Anatomy and Physiology, Regulation of Testosterone Production, CC BY 4.0 as released before 2026-04-23 |
| lichen-on-bark | figure | MallardTV, Wikimedia Commons, CC0 |
| lichen-pollution-indicator | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| lichen-section | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| liger | figure | Asm sultan, Khulna Zoo, Wikimedia Commons, CC0 |
| light-reactions-thylakoid | figure | OpenStax, Biology 2e (Figure 8.2.8, light-dependent reactions), CC BY 4.0 as released before 2026-04-23 |
| lightning-conductor-corona | figure | Composite: lightning conductor by Lukas Beck, CC BY 4.0; corona discharge by NataliiaBashmakova, CC BY 4.0; via Wikimedia Commons |
| liliaceae-bulb-ovary | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| lily-anthers-and-stigma-photo | figure | PDphoto.org, Stamens and pistil of a lily, public domain; via Wikimedia Commons |
| limbic-system | figure | OpenStax College, Wikimedia Commons, CC BY 3.0 |
| limescale-pot | figure | Nicbou, Limescale deposit in a cooking pot, CC0, via Wikimedia Commons |
| lippes-loop-iud | figure | Chalklet AI Labs, drawn for this project (figures/pic2_drawings.py) - owned |
| lithium-caesium-water | figure | Chalklet AI Labs, drawn for this project (figures/pic2_drawings.py) - owned |
| liver-fluke-two-hosts | figure | CDC DPDx, Clonorchis sinensis life cycle, CC BY 4.0 as given on Commons (CDC work); via Wikimedia Commons, labelled by Chalklet AI Labs; logos removed |
| liverwort-life-cycle | figure | OpenStax, Biology 2e (Figure 25.3.3, Bryophytes), CC BY 4.0 as released before 2026-04-23 |
| lorry-photo | figure | USDA Forest Service Region 6 State and Private Forestry, 1938 Loaded log truck on steep grade - Tillamook Burn Oregon, public domain, via Wikimedia Commons |
| lunar-retroreflector | figure | NASA, Apollo 11, public domain, via Wikimedia Commons |
| lung-pleura | figure | OpenStax College, Anatomy and Physiology, CC BY 3.0 |
| lymph-capillaries-blind | figure | OpenStax, Biology 2e (modification of work by NCI), CC BY 4.0 |
| lymphatic-system | figure | BruceBlaus, Wikimedia Commons, CC BY 3.0 |
| lysosome-functions | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| macrophage-phagocytosis | figure | OpenStax College, Biology 2e, CC BY 4.0 as released before 2026-04-23 |
| magnetron-cutaway | figure | US government training manual drawing, public domain, via Wikimedia Commons |
| maize-castor-seeds | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| maize-monoecious | figure | OpenStax College, Biology 2e, Figure 32.1.3 (corn plant), CC BY 4.0 as released before 2026-04-23, after a public-domain Koehler engraving; key added by Chalklet AI Labs |
| male-reproductive-system | figure | Ruth Lawson, Otago Polytechnic - Anatomy and Physiology of Animals, via Wikimedia Commons - CC BY 3.0 |
| malpighian-tubules | figure | OpenStax, Biology 2e, CC BY 4.0, via Wikimedia Commons |
| malvaceae-details | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| mammal-heart-and-red-cell | figure | Composite: heart section from Blausen Medical (WikiJournal of Medicine 2014), CC BY 3.0, as registered; red blood cell from Servier Medical Art, CC BY 3.0; via Wikimedia Commons |
| marchantia | figure | DataBase Center for Life Science (DBCLS), via Wikimedia Commons - CC BY 4.0 |
| marsupial-radiation | figure | Ivan Lojko (kangaroo), Dinkum (koala), sugar glider photographer unnamed, Daderot (Tasmanian devil), all CC0, via Wikimedia Commons; cropped and labelled by Chalklet |
| megakaryocyte-platelets | figure | explorebiology, XBio illustration - Megakaryocyte, CC BY 4.0, via Wikimedia Commons |
| megasporogenesis | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| meiosis-anaphase-i | figure | Shreelaya Katha, via Wikimedia Commons (Meiosis_Wikipedia.jpg) - CC BY 4.0; cropped 2026-10-15 to the Anaphase I panel of the plate, the 'Crossover genes' label and its leader masked, neighbouring panels' arrows and label fragments masked; the whole plate is not registered because three of its labels are false (gametes 'genetically similar', 'Random Assortment' on prophase I, 'Centrioles dissolve') |
| meiosis-anaphase-ii | figure | Shreelaya Katha, via Wikimedia Commons (Meiosis_Wikipedia.jpg) - CC BY 4.0; cropped 2026-10-15 to the Anaphase II panel of the plate (both daughter cells), neighbouring panels' arrows and label fragments masked; the whole plate is not registered because three of its labels are false (gametes 'genetically similar', 'Random Assortment' on prophase I, 'Centrioles dissolve') |
| meiosis-four-products | figure | Shreelaya Katha, Meiosis_Wikipedia.jpg, Wikimedia Commons, CC BY 4.0; cropped to the four product cells, the false label '4 genetically similar gametes' and the 'Centrioles dissolve' label masked |
| meiosis-kinetochores | figure | OpenStax, Biology 2e (Figure 11 01 04), via Wikimedia Commons - CC BY 4.0 |
| meiosis-metaphase-i | figure | Shreelaya Katha, via Wikimedia Commons (Meiosis_Wikipedia.jpg) - CC BY 4.0; cropped 2026-10-15 to the Metaphase I panel of the plate, neighbouring panels' arrows and a label fragment masked; the whole plate is not registered because three of its labels are false (gametes 'genetically similar', 'Random Assortment' on prophase I, 'Centrioles dissolve') |
| meiosis-metaphase-ii | figure | Shreelaya Katha, via Wikimedia Commons (Meiosis_Wikipedia.jpg) - CC BY 4.0; cropped 2026-10-15 to the Metaphase II panel of the plate (both daughter cells), neighbouring panels' arrows and label fragments masked; the whole plate is not registered because three of its labels are false (gametes 'genetically similar', 'Random Assortment' on prophase I, 'Centrioles dissolve') |
| mendel-seven-traits | figure | OpenStax, Concepts of Biology (Figure 8.1.3), CC BY 4.0 as released before 2026-04-23 |
| meningeal-layers-arachnoid | figure | OpenStax College, Anatomy and Physiology, Meningeal Layers of Superior Sagittal Sinus, CC BY 4.0 as released before 2026-04-23 |
| meninges | figure | BruceBlaus, Wikimedia Commons, CC BY 3.0 |
| menstrual-cycle-phases | figure | OpenStax, Biology 2e (Figure 43.4.4), CC BY 4.0, via Wikimedia Commons |
| meristem-locations | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| meristem-virus-free | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| metagenesis-polyp-medusa | figure | Philcha, Wikimedia Commons, public domain |
| metal-detector-beach-photo | figure | Don DeBold, Looking for Treasure on the Beach, CC BY 2.0, via Wikimedia Commons |
| methyl-alpha-D-glucoside | figure | Edgar181, via Wikimedia Commons - public domain |
| micelle | figure | AlineSP, Wikimedia Commons, CC BY 4.0 |
| microbial-products-in-use | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| microbody-single-membrane | figure | OpenStax, Anatomy and Physiology 2e (0316 Peroxisome), CC BY 4.0 as released before 2026-04-23; the label Plasma membrane replaced by Single membrane and a heading added by Chalklet |
| microphyll-macrophyll-fern | figure | i_c_riddell (Selaginella kraussiana, CC BY 4.0) and Craig Pemberton (Circinate vernation, CC BY 2.0); via Wikimedia Commons, set side by side and labelled by Chalklet AI Labs |
| micropropagation-plantlets | figure | Chanokpat Kijkar, Wikimedia Commons, CC BY 4.0 |
| middle-ear-ossicles | figure | Blausen.com staff (2014). Medical gallery of Blausen Medical 2014. WikiJournal of Medicine 1(2). CC BY 3.0, via Wikimedia Commons; cropped to the middle-ear inset, whole-ear section removed |
| miller-urey | figure | Carny, Wikimedia Commons, CC BY 2.5 |
| mirror-galvanometer-lamp-scale | figure | Norman Hugh Schneider and Silvanus P. Thompson, public domain, via Wikimedia Commons |
| mitochondrion | figure | Mariana Ruiz Villarreal (LadyofHats), via Wikimedia Commons - public domain - modified 2026-10-15: the label 'inter membrane space' respelt 'intermembrane space' (NCERT spelling); drawing unchanged |
| mitosis-cutting-tumour | figure | Waithamai, Basilikumwurzling, Wikimedia Commons, CC BY 4.0; Rao and Ryan, Cell Division and Apoptosis, OpenStax Biology, CC BY 4.0 as released before 2026-04-23; layout by Chalklet AI Labs |
| mitosis-identical-daughters | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| mitosis-phases | figure | OpenStax, Biology 2e (Figure 10.2.2), CC BY 4.0 as released before 2026-04-23 |
| mitosis-prophase-centrosomes | figure | Mariana Ruiz Villarreal (LadyofHats), via Wikimedia Commons - public domain; cropped 2026-10-15 to the first two panels (prophase and prometaphase) of the six-panel strip |
| mixtures-test-tubes | figure | Mvolz, Wikimedia Commons, CC0 (white ground added) |
| mollusc-anatomy | figure | OpenStax, Biology 2e (Figure 28 03 08), via Wikimedia Commons - CC BY 4.0 |
| mollusc-kidney-mantle-cavity | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py), re-drawn from the Encyclopaedia Britannica (1911) 'Mollusca' fig. 6, after Lankester (public domain) - owned |
| mollusc-shell-states | figure | Naturalis Biodiversity Center (Pila globosa shell, CC0); Philip Henry Gosse (cuttlebone, public domain); James H. Emerton (Loligo pealeii gladius, public domain); OpenStax Biology 2e Figure 28.3.14 d (octopus, CC BY 4.0, after Angell Williams); via Wikimedia Commons and OpenStax, cropped and labelled by Chalklet |
| monascus-purpureus | figure | DataBase Center for Life Science (DBCLS), Wikimedia Commons, CC BY 4.0 |
| monocot-leaf-bulliform | figure | Berkshire Community College Bioscience Image Library, The Monocotyledonous Leaf of Zea and Bulliform Cells in Zea Leaf, CC0; via Wikimedia Commons, labelled by Chalklet AI Labs |
| moss-antheridia-archegonia | figure | OpenStax, Biology 2e (Figure 25.3.6), CC BY 4.0; two panels cropped, the label Venter re-lettered Archegonia (its leaders end on the archegonia), neck and venter labels added by Chalklet |
| moss-funaria | figure | original: LadyofHats, derivative: Masur, via Wikimedia Commons - public domain |
| moss-liverwort-details | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| motor-sensory-cortex | figure | Blausen.com staff (2014). Medical gallery of Blausen Medical 2014. WikiJournal of Medicine 1(2). CC BY 3.0, via Wikimedia Commons; title cropped |
| mould-culture-plate | figure | Dr. Lucille K. Georg, CDC Public Health Image Library, public domain |
| moving-coil-galvanometer | figure | Maxmath12, Wikimedia Commons, CC0 |
| mri-brain-tumour-slice | figure | NCI-CONNECT Staff, MRI of PNET, public domain (US NCI), via Wikimedia Commons |
| mule-worker-bee | figure | Anthony Baratier, Mule in Santorini, CC0; Scott Bauer (USDA ARS), Apis mellifera scutellata 1355021, public domain; via Wikimedia Commons, cropped and labelled by Chalklet |
| multipolar-neuron | figure | Blausen.com staff (2014). Medical gallery of Blausen Medical 2014. WikiJournal of Medicine 1(2). CC BY 3.0, via Wikimedia Commons; label Telodendria masked and rewritten as Axon terminals |
| muscle-fibre-organisation | figure | OpenStax, Anatomy and Physiology, CC BY 4.0 |
| muscle-locations | figure | Blausen.com staff (2014), Medical gallery of Blausen Medical 2014, WikiJournal of Medicine, CC BY 3.0 (knee, cropped); with OpenStax College, Anatomy and Physiology, Layers of the Gastrointestinal Tract and Layers of the Heart Wall, CC BY 4.0 as released before 2026-04-23; set side by side and captioned by Chalklet AI Labs |
| muscle-three-types | figure | OpenStax College, Anatomy and Physiology, Skeletal, Smooth and Cardiac Muscle (micrographs provided by the Regents of University of Michigan Medical School 2012), CC BY 4.0 as released before 2026-04-23; key added by Chalklet AI Labs |
| mycoplasma-no-wall | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| mycorrhiza | figure | Rajarshi Rit, Wikimedia Commons, CC BY 4.0 |
| myelinated-nerve-fibre | figure | Mariana Ruiz Villarreal (LadyofHats), Wikimedia Commons, public domain |
| myofilaments | figure | OpenStax (Anatomy and Physiology, Thick and Thin Filaments), via Wikimedia Commons - CC BY 4.0 |
| naked-vs-enclosed-ovule | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| nematocyst-discharge | figure | Philcha, Wikimedia Commons, public domain |
| nematode-long-section | figure | OpenStax, Biology 2e (Figure 28.4.1 b), CC BY 4.0; one panel cropped, title and caption by Chalklet |
| nephron-blood-supply | figure | OpenStax College, Anatomy and Physiology (Figure 25.11), CC BY 3.0, via Wikimedia Commons |
| nephron-structure | figure | Holly Fischer, Wikimedia Commons, CC BY 3.0 |
| nephron-vasa-recta | figure | Henry Vandyke Carter, Gray's Anatomy (1918) Fig. 1128, public domain, via Wikimedia Commons; the label Arteriae rectae replaced by vasa recta by Chalklet |
| nerve-cord-dorsal-ventral | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| nerve-impulse-conduction | figure | Dr. Jana (Saltatory Conduction, frame 15 of 36), CC BY 4.0, via Wikimedia Commons |
| nervous-systems-compared | figure | OpenStax, Biology 2e (Figure 35.1.1), CC BY 4.0, via Wikimedia Commons |
| neuromuscular-junction | figure | Doctor Jana, docjana.com, Wikimedia Commons, CC BY 4.0 |
| neuron-nissl | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| neuron-structure | figure | NIH BioArt Source, National Institutes of Health - public domain |
| neuron-types | figure | OpenStax, Anatomy and Physiology, CC BY 4.0 |
| neutrophil-amoeboid | figure | Volker Brinkmann, Neutrophil with anthrax, CC BY 2.5, via Wikimedia Commons, labelled by Chalklet |
| newborn-skull-fontanelles | figure | OpenStax College, 702 Newborn Skull (Anatomy and Physiology), CC BY 3.0, via Wikimedia Commons |
| nk-cell-mhc | figure | OpenStax College, Biology 2e, CC BY 4.0 as released before 2026-04-23 |
| nondisjunction-meiosis | figure | OpenStax, Biology for AP Courses (Figure 13.3.2, Chromosomal Basis of Inherited Disorders), CC BY 4.0 as released before 2026-04-23 |
| normal-vein-valve | figure | Blausen.com staff (2014). Medical gallery of Blausen Medical 2014. WikiJournal of Medicine 1(2). CC BY 3.0, via Wikimedia Commons; cropped to the normal vein panel |
| notochord-to-vertebrae | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| nuclear-envelope-pores | figure | Mariana Ruiz LadyofHats, Wikimedia Commons, public domain |
| nuclear-lamina | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| nucleoid-vs-nucleus | figure | Science Primer (National Center for Biotechnology Information), vectorised, Celltypes, public domain, via Wikimedia Commons (one label corrected); envelope inset and notes drawn by Chalklet AI Labs |
| nucleolus-nor | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| nucleosome-chromatin | figure | Xi-Chen, via BioIcons - CC0 |
| nucleosome-chromatin-packing | figure | OpenStax, Biology 2e (Figure 10.1.3, chromatin packing), CC BY 4.0 as released before 2026-04-23 |
| nucleus-nucleolus | figure | Servier Medical Art, via BioIcons - CC BY 3.0 |
| occipital-condyles | figure | OpenStax College, Anatomy and Physiology, Inferior View of Skull Base, CC BY 4.0 as released before 2026-04-23; key added by Chalklet AI Labs |
| octopus-eye | figure | incidencematrix, Octopus Eye, CC BY 2.0; via Wikimedia Commons, labelled by Chalklet AI Labs |
| oleander-stomatal-crypts | figure | Truong Minh Khai, CC BY 4.0, via Wikimedia Commons; cropped and labelled by Chalklet |
| onion-root-prophase | figure | Ibn Anvar, Mitosis in Onion Root Tip (CC0), via Wikimedia Commons; cropped and labelled by Chalklet |
| oocyte-meiosis-completes | figure | OpenStax, Anatomy and Physiology 2e, Oogenesis (section 27.2), CC BY 4.0 |
| opium-poppy-latex | figure | KGM007, opium poppy pod cut to show latex, public domain, via Wikimedia Commons |
| opuntia-phylloclade | figure | Tangopaso, Opuntia (cladode), public domain; via Wikimedia Commons, labelled by Chalklet AI Labs |
| orange-and-mango | figure | Noblevmy at ml.wikipedia (Alphonso mango), CC BY 2.5; with USDA Agricultural Research Service (Ambersweet oranges, ID k3644-12, public domain); via Wikimedia Commons, cropped and set side by side by Chalklet |
| orbital-shapes | figure | Benjah-bmm27, Wikimedia Commons, public domain |
| orchard-frost-ice | figure | Haneburger, Wikimedia Commons, public domain |
| organ-pipes-photo | figure | Thomas Quine, Organ pipes, CC BY 2.0, via Wikimedia Commons |
| organelle-fission | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| organelle-micrographs | figure | OpenStax, via Wikimedia Commons - CC BY 4.0; cropped from the page figures |
| ossicles-endoskeleton | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| osteoarthritis-hip | figure | OpenStax College, Anatomy and Physiology (Figure 9.9), CC BY 4.0, via Wikimedia Commons |
| osteoporosis-bone | figure | Blausen.com staff (2014). Medical gallery of Blausen Medical 2014. WikiJournal of Medicine 1(2). CC BY 3.0, via Wikimedia Commons |
| out-of-africa-map | figure | Altaileopard, Spreading homo sapiens, public domain, via Wikimedia Commons; legend translated from Norwegian to English by Chalklet |
| ovary-cortex-medulla | figure | OpenStax, Biology for AP Courses (Figure 43.3.6, human ovary), CC BY 4.0 as released before 2026-04-23 |
| ovary-follicles | figure | OpenStax, Anatomy and Physiology 2e (Figure 28.2.4 a), CC BY 4.0; panel (a) only, title and caption by Chalklet |
| ovary-position-hypo-epi | figure | OpenStax College, Biology 2e, Figure 32.1.4 (superior and inferior flowers), CC BY 4.0 as released before 2026-04-23; key added by Chalklet AI Labs |
| over-exploitation-sea-cow-pigeon | figure | Daderot (Steller sea cow skeleton, Finnish Museum of Natural History, CC0) and K. Hayashi (passenger pigeon painting, public domain); via Wikimedia Commons, labelled by Chalklet AI Labs |
| ovule-structure | figure | biologia.edu.ar, trace and colour by RoRo, via Wikimedia Commons - public domain |
| oxy-acetylene-cutting-torch-photo | figure | Unknown author, Cutting torch, public domain, via Wikimedia Commons |
| paddy-cyanobacteria | figure | Naithik Shetty, Planted Paddy Field (CC0); Anabaena micrograph (CC0); via Wikimedia Commons, cropped and labelled by Chalklet |
| papaya-dioecious | figure | Forest and Kim Starr (Carica papaya male flowers, CC BY 3.0 US) and Elivis256 (papaya fruits, CC0); via Wikimedia Commons, set side by side and labelled by Chalklet AI Labs |
| paramecium | figure | OpenStax, Biology 2e (Figure 23 03 06ab), via Wikimedia Commons - CC BY 4.0; cropped to the labelled diagram (the title bar and the micrograph removed) |
| paramecium-amoeba | figure | Composite: Paramecium from OpenStax Biology 2e, CC BY 4.0; Amoeba proteus by Joseph Leidy (1879), public domain; via Wikimedia Commons |
| parasympathetic-innervation | figure | Blausen.com staff (2014). Medical gallery of Blausen Medical 2014. WikiJournal of Medicine 1(2). CC BY 3.0, via Wikimedia Commons; cropped, title removed |
| parthenium-weed | figure | Apurv013, Wikimedia Commons, CC0 |
| parthenocarpic-tomato | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| pbr322-map | figure | Nothingserious, via Wikimedia Commons - CC0 |
| pct-brush-border | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py), re-drawn from public-domain plates (see drawn.reference) - owned |
| pelvis-anterior | figure | Blausen.com staff (2014). Medical gallery of Blausen Medical 2014. WikiJournal of Medicine 1(2). CC BY 3.0, via Wikimedia Commons; cropped to the anterior view, skeleton inset and posterior view removed |
| pencil-refraction | figure | Franklin Kerber, Wikimedia Commons, public domain (white ground added) |
| penicillin-inhibition-plate | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| penicillium | figure | Dr Lucille K. Georg, CDC Public Health Image Library, public domain |
| pericardial-sac | figure | Blausen.com staff (2014). Medical gallery of Blausen Medical 2014. WikiJournal of Medicine 1(2). CC BY 3.0, via Wikimedia Commons; cropped, title removed |
| pericarp-fleshy-dry | figure | Judgefloro (guava, CC0); David E Mead (groundnuts, CC0); via Wikimedia Commons, cropped and labelled by Chalklet |
| periodic-table | figure | Offnfopt, Wikimedia Commons, public domain |
| phagocytosis | figure | OpenStax, Biology 2e (Figure 05 04 01), via Wikimedia Commons - CC BY 4.0 |
| phet-greenhouse-effect | figure | Simulation by PhET Interactive Simulations, University of Colorado Boulder, licensed under CC BY 4.0 (https://phet.colorado.edu); default screenshot, credit line printed under it |
| phet-protons-neutrons-electrons | figure | Simulation by PhET Interactive Simulations, University of Colorado Boulder, licensed under CC BY 4.0 (https://phet.colorado.edu); default screenshot, credit line printed under it |
| photoelastic-fringes | figure | Trociny-fotografujo, Wikimedia Commons, CC0 |
| photorespiration-organelles | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| photosynthesis-experiments | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| photosystem | figure | Govindjee and Dmitriy Shevela, Frontiers in Plant Science, CC BY 3.0 |
| photosystem-light-harvesting | figure | OpenStax, Biology 2e (Figure 8.2.7), CC BY 4.0, via Wikimedia Commons |
| phragmoplast-cell-plate | figure | Miguelferig, Cell plate, CC0; with Tameeria, Phragmoplast, public domain; via Wikimedia Commons; key and middle-lamella inset drawn by Chalklet AI Labs |
| phyllotaxy | figure | Pearson Scott Foresman, via Wikimedia Commons - public domain |
| pigment-chromatogram | figure | Servier Medical Art, via BioIcons - CC BY 3.0 |
| pila-mollusc | figure | Al2, via Wikimedia Commons - CC BY 3.0 |
| pine-annual-rings | figure | Berkshire Community College Bioscience Image Library, Gymnosperm Stem Spring and Summer Wood in Four Year Pinus, CC0; via Wikimedia Commons, labelled by Chalklet AI Labs |
| pine-cones-sporophylls | figure | Encyclopaedia Britannica 1911 (Pine, Figs. 1-2), public domain, via Wikimedia Commons; key letters re-lettered as English labels from the 1911 caption by Chalklet |
| pine-pollen-tube | figure | OpenStax, Biology 2e (Figure 26.2.1), CC BY 4.0; one panel cropped, a layout arrow painted over, caption by Chalklet |
| pineapple-flowering | figure | Flocci Nivis, Ananas comosus (2026-03-17), CC BY 4.0, via Wikimedia Commons, cropped and labelled by Chalklet |
| pinus-needle-ginkgo | figure | sgharvey (Pinus needle cross-section, CC BY 2.0) and Atlas the Biologist (Ginkgo biloba leaf, CC BY 4.0); via Wikimedia Commons, set side by side and labelled by Chalklet AI Labs |
| pinus-strobili | figure | Encyclopaedia Britannica 1911 (Fig. 1 and Fig. 2, Scotch Fir / Pinus sylvestris), via Wikimedia Commons - public domain |
| pistil-ovule-ls | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| pituitary-sella-turcica | figure | OpenStax, Anatomy and Physiology 2e (Pituitary Tumor figure, normal-pituitary panel only), CC BY 4.0 as released before 2026-04-23 |
| placenta | figure | OpenStax College, Wikimedia Commons, CC BY 3.0 |
| placentation | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| placoid-scales | figure | Javier Guallart, Dalatias licha skin SEM (CC BY 4.0), via Wikimedia Commons; cropped (photo credit line below the frame) and labelled by Chalklet |
| planaria | figure | Encyclopaedia Britannica 1911 (Planarians - Plan of a Tricladid), via Wikimedia Commons - public domain |
| plane-mirror-reflection-photo | figure | Enrico Carcasci, Mirror (Unsplash), CC0, via Wikimedia Commons |
| plant-body | figure | Pearson Scott Foresman (node/internode panel, public domain) and Mariana Ruiz Villarreal LadyofHats (terminal bud and axillary bud panels, cc0), via Wikimedia Commons |
| plant-cell | figure | LadyofHats (Mariana Ruiz Villarreal), via Wikimedia Commons - public domain |
| plant-size-extremes | figure | Christian Berg (Wolffia arrhiza, CC BY 4.0) and Melburnian (Eucalyptus regnans, CC BY 3.0), via Wikimedia Commons |
| plant-tissue-culture | figure | Viktor Husak, own work, CC0, via Wikimedia Commons |
| plasma-membrane | figure | Mariana Ruiz Villarreal, Wikimedia Commons, public domain |
| plasmodium-life-cycle | figure | OpenStax, Biology for AP Courses (Figure 23.3.5b, Plasmodium life cycle), CC BY 4.0 as released before 2026-04-23; cropped to panel (b), the words produced by meiosis removed from step 5 |
| plasmodium-ring-stages | figure | Michael Zahniser, Wikimedia Commons, public domain |
| plaster-cast-sculpture-photo | figure | Wellcome Images, Plaster cast from sculpture of John Snow by Ruth Poynter, CC BY 4.0, via Wikimedia Commons |
| plastid-interconversion | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| pneumatophores | figure | pinay06, Wikimedia Commons, CC BY 2.5 |
| pneumococcus-capsule | figure | CDC (PHIL 2113), Pneumococcus capsule stain, public domain, via Wikimedia Commons, cropped and labelled by Chalklet |
| pneumonia-alveoli | figure | Composite of US government source images, Wikimedia Commons, public domain |
| pollen-grain | figure | via Wikimedia Commons - public domain |
| pollen-grain-development | figure | OpenStax, Biology 2e (Figure 32.1.6), CC BY 4.0, via Wikimedia Commons |
| pollen-three-celled | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py), re-drawn from OpenStax Biology 2e Fig. 32.1.6 (CC BY 4.0) - owned |
| pollen-tube-entry-synergid | figure | Fatema U, Ali MF, Hu Z, Clark AJ and Kawashima T, Gamete Nuclear Migration in Animals and Plants, Frontiers in Plant Science 10:517 (2019), Figure 7 - CC BY 4.0 |
| polyembryony-apomictic-hybrid | figure | Peter Woodard, Syzygium Polyembryony seeds, Wikimedia Commons, CC0; fields drawn by Chalklet AI Labs |
| polynucleotide-chain | figure | Thomas Shafee, via Wikimedia Commons - CC BY 4.0, modified 2026-09-01: root fill #E6E6E6 added so ink that set no fill of its own renders light on the dark board - geometry, glyphs and the base colours unchanged |
| polyp-and-medusa | figure | Philcha, Wikimedia Commons, public domain |
| polyploid-daylily | figure | Steve Karg, Orange Daylily, CC BY 2.5, via Wikimedia Commons, labelled by Chalklet |
| polysome-mrna | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| polytene-chromosomes | figure | LPLT, Wikimedia Commons, public domain |
| pomato-somatic-hybrid | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| pond-water | figure | USFWS Pacific Southwest Region, Fish Lake Valley tui chub habitat, public domain, via Wikimedia Commons |
| porphyra-laver-sheets | figure | Hugh McCormick Smith, The seaweed industries of Japan (Bulletin of the US Bureau of Fisheries, 1904), public domain, via Wikimedia Commons (FMIB 41746); labelled by Chalklet |
| posterior-pituitary-complex | figure | OpenStax College, Anatomy and Physiology, CC BY 3.0; modified 2026-10-20: the two nucleus names and the upper OT/ADH labels were replaced by a neutral 'Neurosecretory cells' label, because the plate paired the supraoptic nucleus with OT and the paraventricular with ADH, the reverse of standard teaching |
| potash-alum-crystal | figure | Vanadict, Wikimedia Commons, CC0 |
| potato-eyes-nodes | figure | ZooFari, Potato with sprouts, public domain; via Wikimedia Commons, labelled by Chalklet AI Labs |
| power-transformer-photo | figure | Antti Leppanen, electrical substation transformer in Muurame (cropped), CC BY 4.0, via Wikimedia Commons |
| pregnancy-uterus | figure | Blausen.com staff (2014). Medical gallery of Blausen Medical 2014. WikiJournal of Medicine 1(2). CC BY 3.0, via Wikimedia Commons; cropped, caption removed |
| pressure-cooker-photo | figure | Your Best Digs, electric pressure cooker, CC BY 2.0, via Wikimedia Commons |
| priestley-bell-jar | figure | PigeonShaman, Priestley mouse (CC0), via Wikimedia Commons; cropped and labelled by Chalklet |
| primary-secondary-growth | figure | OpenStax, Biology 2e, CC BY 4.0, via Wikimedia Commons |
| primrose-pin-thrum | figure | Primrose pin and Primrose thrum photographs (public domain), via Wikimedia Commons; cropped and labelled by Chalklet |
| prism-spectrum-photo | figure | Kelvinsong, Prism flat rainbow, CC0, via Wikimedia Commons |
| proinsulin | figure | Mr Hyde at Czech Wikipedia, Wikimedia Commons, public domain |
| prokaryotic-cell | figure | Servier Medical Art, via Bioicons - CC BY 3.0 |
| prophase-centrosomes | figure | Roy van Heesbeen, via Wikimedia Commons - public domain |
| prophase-spindle-animal-plant | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| protein-denaturation | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| protein-denaturation-food | figure | Composite: fried egg by David Benbennick, public domain; ricotta curds by 8w9d, CC0; via Wikimedia Commons |
| protein-four-levels | figure | OpenStax, Biology 2e (Figure 3.4.9, levels of protein structure), CC BY 4.0 as released before 2026-04-23 |
| protein-helix-sheet-hbonds | figure | OpenStax, Biology 2e (Figure 3.4.7; the plate's two proportional signs corrected to alpha), CC BY 4.0 as released before 2026-04-23 |
| protein-primary-structure | figure | DataBase Center for Life Science (DBCLS), via BioIcons, CC BY 4.0; the embedded bitmap, cropped |
| protein-quaternary-structure | figure | DataBase Center for Life Science (DBCLS), via BioIcons and Wikimedia Commons, CC BY 4.0; the embedded bitmap, cropped |
| protein-secondary-structure | figure | DataBase Center for Life Science (DBCLS), via BioIcons and Wikimedia Commons, CC BY 4.0; the embedded bitmap, cropped |
| protein-structure-levels | figure | DataBase Center for Life Science (DBCLS), via BioIcons - CC BY 4.0 |
| psilotum-equisetum | figure | James St. John (Psilotum nudum, CC BY 2.0) and Dcrjsr (Equisetum arvense, CC BY 4.0); via Wikimedia Commons, set side by side and labelled by Chalklet AI Labs |
| pump-and-aerosol-photo | figure | Composite: U.S. Consumer Product Safety Commission, bike pump, public domain; Mikael Haggstrom, freeze spray, CC0; via Wikimedia Commons; captions added |
| raindrop-mist-photo | figure | W.carter, Morning mist lifting from plowed field 3, CC0, via Wikimedia Commons |
| rauvolfia-two-plants-photo | figure | Forestowlet, Rauvolfia serpentina in FRLHT Bangalore, CC0; P Jeganathan, Rauvolfia serpentina, CC BY 4.0; via Wikimedia Commons, composited by Chalklet |
| rbc-mammal-amphibian | figure | Hand-book of Physiology (1892), Internet Archive Book Images, no known copyright restrictions, via Wikimedia Commons; two rows cropped and labelled by Chalklet |
| rebreather-breathing-apparatus-photo | figure | Staff Sgt. Laura Bauer, 2023 GDF Drager rebreather, public domain (US military), via Wikimedia Commons |
| red-alga-polysiphonia | figure | Anonymous, Polysiphonia filiformis herbarium sheet, public domain; via Wikimedia Commons, set side by side and labelled by Chalklet AI Labs |
| red-tide-bloom | figure | Xavier Caisey (Ifremer), CC BY 4.0, via Wikimedia Commons; labelled by Chalklet |
| red-white-breast-muscle | figure | Ryan Snyder, Duck Breasts, Flickr via Wikimedia Commons, CC BY 2.0; chicken breast by Dnor, Wikimedia Commons, public domain; layout and labels by Chalklet AI Labs |
| reflex-arc-two-neuron | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| refracting-reflecting-telescopes | figure | OpenStax Astronomy, CC BY 4.0, via Wikimedia Commons |
| renal-corpuscle | figure | NIH NIAID, BioArt Source, Wikimedia Commons, CC BY 4.0 |
| replication-fork | figure | Masur, via Wikimedia Commons - CC BY 2.5 |
| reptile-anatomy | figure | Internet Archive Book Images, 'Chordate Anatomy' (1939), Wikimedia Commons, public domain |
| reptile-vs-crocodile-heart | figure | Left: OpenStax, Biology 2e (Figure 40.1.3c), CC BY 4.0. Right: Nascimento M, Maggio G, de Almeida M et al., Anatomia Histologia Embryologia 55 (2026), Figure 1F, CC BY 4.0; codes RV, LV, IVS re-lettered in English |
| resonance-column-drawn | figure | Chalklet AI Labs, drawn for this project (tools/draw_physics_apparatus.py) - owned |
| respiratory-epithelium | figure | Blausen.com staff (2014). Medical gallery of Blausen Medical 2014. WikiJournal of Medicine 1(2). CC BY 3.0, via Wikimedia Commons; cropped to the inset, body figure removed |
| respiratory-system | figure | LadyofHats, Jmarchn, via Wikimedia Commons - public domain |
| respiratory-system-overview | figure | Blausen.com staff (2014). Medical gallery of Blausen Medical 2014. WikiJournal of Medicine 1(2). CC BY 3.0, via Wikimedia Commons; cropped, title removed |
| restriction-site | figure | Bryan Derksen, Wikimedia Commons, public domain (white background rect added for legibility on a dark canvas) |
| rh-erythroblastosis | figure | OpenStax, Anatomy and Physiology (Figure 21.30, Erythroblastosis Fetalis), CC BY 4.0 as released before 2026-04-23 |
| rheumatoid-hands | figure | Dr. Gannavarapu Narasimhamurthy, Severely deformed hands from Rheumatoid Arthritis, CC0, via Wikimedia Commons, cropped and labelled by Chalklet |
| rib-cage-true-false-floating | figure | OpenStax College, Anatomy and Physiology, Thoracic Cage, CC BY 4.0 as released before 2026-04-23; key added by Chalklet AI Labs |
| ringworm-lesion | figure | Dr. Lucille K. Georg, CDC Public Health Image Library, public domain |
| ringworm-sites | figure | CDC Public Health Image Library 4809 and Ellington (Athletes foot), Wikimedia Commons, public domain; body outline and labels by Chalklet AI Labs |
| ripe-banana-among-unripe-photo | figure | Rosendahl, Green and yellow bananas, public domain, via Wikimedia Commons |
| rnai-meloidogyne-tobacco | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| road-salt-store | figure | US Air National Guard photo by Tech. Sgt. Jorge Intriago, public domain, via Wikimedia Commons |
| rock | figure | W.carter, Mossy boulders at Myrstigen track 2, CC0, via Wikimedia Commons |
| rock-salt-lattice | figure | Benjah-bmm27, Wikimedia Commons, public domain |
| rocket-launch-photo | figure | Carleton Bailie, United Launch Alliance Delta II launch with GPS IIR-20, public domain (US Air Force), via Wikimedia Commons |
| root-cap-ink-marks | figure | Strasburger, Noll, Schenck and Schimper, Lehrbuch der Botanik 4th ed. (1900), barley root tip section, public domain; via Wikimedia Commons; ink-mark panel drawn and key added by Chalklet AI Labs |
| root-nodule | figure | Albert Schneider, Pharmaceutical Bacteriology 1920, public domain |
| root-systems | figure | Pearson Scott Foresman (taproot, fibrous root panels) and Encyclopaedia Britannica 1911 (Ficus prop-root panel), via Wikimedia Commons - public domain |
| root-tip-regions | figure | New Student Reference Work (1914), via Wikimedia Commons - public domain |
| root-tip-zones | figure | OpenStax, Biology 2e (Figure 30 03 02), via Wikimedia Commons - CC BY 4.0 |
| root-ts | figure | Berkshire Community College Bioscience Image Library, via Wikimedia Commons - CC0 (dicot: Ranunculus root T.S.; monocot: Zea mays root T.S.) |
| roquefort-blue-cheese | figure | Jon Sullivan, PDphoto.org, public domain |
| rubisco-competition | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| sacred-groves-map | figure | NASA Blue Marble, Indian Subcontinent, public domain, via Wikimedia Commons (cropped); region marks and labels drawn by Chalklet AI Labs |
| salt-evaporation-pond | figure | Anfecaro, Wikimedia Commons, CC0 |
| sarcomere-bands | figure | via Wikimedia Commons - CC BY 2.5 |
| sarcomere-em | figure | Loison O, Weitkunat M, Kaya-Copur A et al. (PLoS Biology 2018), Sarcomero M-Z, CC BY 4.0, via Wikimedia Commons; cropped |
| sarcomere-tem | figure | Louisa Howard, Dartmouth Electron Microscope Facility, human skeletal muscle TEM, public domain, via Wikimedia Commons |
| screw-gauge-photo | figure | Nicolas Buffler, outside micrometer (screw gauge), CC BY 2.0, via Wikimedia Commons |
| scuba-diver-underwater-photo | figure | National Oceanic and Atmospheric Administration, NOAA scuba diver surveying bleached corals, CC0, via Wikimedia Commons |
| sea-star-anatomy | figure | OpenStax, Biology 2e, CC BY 4.0, via Wikimedia Commons |
| seal-blubber | figure | LufkinF, Harbor seal in Holyoke, Connecticut River (CC0), via Wikimedia Commons; cropped and labelled by Chalklet |
| secondary-growth | figure | Encyclopaedia Britannica 1911 (Plants, fig. 24 - three-year-old lime stem, after Kny), via Wikimedia Commons - public domain; the letter codes re-lettered as names |
| seed-bank-and-cryo-tank-photo | figure | Dag Endresen, Storage containers in Svalbard Global Seed Vault, public domain; US Department of Energy (NREL), algal cryopreservation system, public domain; via Wikimedia Commons, composited by Chalklet |
| seed-monocot-dicot | figure | OpenStax, Biology 2e (Figure 32.2.9), CC BY 4.0 as released before 2026-04-23; flattened onto white |
| seed-structure-dicot | figure | LadyofHats, via Wikimedia Commons - public domain |
| seismic-velocity-depth | figure | Karla Panchuk, modified after Steven Earle (2016), CC BY 4.0, via Wikimedia Commons |
| self-incompatibility-pistil | figure | National Science Foundation, Genetics of Self-Incompatibility, public domain (US federal work), via Wikimedia Commons; cropped to the two pistil rows |
| setting-sun-photo | figure | Glenn Beltz, Distorted sun at sunset - California, CC BY 2.0, via Wikimedia Commons |
| sewage-flocs-zoogloea | figure | Na Gao, Zoogloea floc vs planktonic, public domain, via Wikimedia Commons, labelled by Chalklet |
| sex-chromosome-aneuploidy | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| shark-anatomy | figure | Chris_huh, Wikimedia Commons, public domain |
| shoot-apex-meristems | figure | Eduard Strasburger, Lehrbuch der Botanik, via the Encyclopaedia Britannica (1911), article Leaf, public domain, via Wikimedia Commons; letter codes replaced by English names by Chalklet |
| shoulder-joint | figure | Blausen.com staff (2014). Medical gallery of Blausen Medical 2014. WikiJournal of Medicine 1(2). CC BY 3.0, via Wikimedia Commons; cropped to the joint, skeleton inset and title removed |
| sickle-cell-sem | figure | OpenStax College, Anatomy and Physiology, CC BY 3.0 |
| sieve-tube-companion | figure | OpenStax College, Biology 2e, Figure 30.5.6 (sieve-tube elements), CC BY 4.0 as released before 2026-04-23 |
| silica-macrophage | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| silicotic-nodule | figure | Silicosis - birefringent under polarized light (public domain), via Wikimedia Commons; cropped below the image, title and labels by Chalklet |
| simple-compound-leaves | figure | OpenStax College, Biology 2e, Figure 30.4.3 (simple and compound leaves), CC BY 4.0 as released before 2026-04-23; key added by Chalklet AI Labs |
| simple-tissues-three | figure | Berkshire Community College Bioscience Image Library, Collenchyma, Sclerenchyma and Parenchyma in Cucurbita, CC0; with an OpenStax College Biology 2e collenchyma micrograph inset, CC BY 4.0 as released before 2026-04-23; labelled by Chalklet AI Labs |
| skeletal-muscle | figure | OpenStax, Anatomy and Physiology, Wikimedia Commons, CC BY 4.0 |
| skeletal-muscle-fibre | figure | Blausen.com staff (2014). Medical gallery of Blausen Medical 2014. WikiJournal of Medicine 1(2). CC BY 3.0, via Wikimedia Commons |
| skin-coverings-seven-classes | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| skin-layers | figure | Blausen.com staff (2014). Medical gallery of Blausen Medical 2014. WikiJournal of Medicine 1(2). CC BY 3.0, via Wikimedia Commons; cropped, title removed |
| skull-cranial-bones | figure | OpenStax College, Anatomy and Physiology, Lateral View of Skull, CC BY 4.0 as released before 2026-04-23; cranial-bone count added by Chalklet AI Labs |
| skull-facial-bones | figure | OpenStax College, Anatomy and Physiology, Anterior View of Skull, CC BY 4.0 as released before 2026-04-23; key added by Chalklet AI Labs |
| skull-sutures | figure | OpenStax College, Anatomy and Physiology, CC BY 3.0 |
| slime-mould-life-cycle | figure | OpenStax, Biology 2e (Figure 23.3.18), CC BY 4.0, via Wikimedia Commons |
| snake-shed-skin | figure | Shed skin of a snake (CC0), via Wikimedia Commons; cropped and labelled by Chalklet |
| snapdragon-incomplete-dominance | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| snow-ice | figure | Jeremy Harbeck, Iceberg in North Star Bay, Greenland, public domain, via Wikimedia Commons |
| soap-bubble-photo | figure | Max Stotsky, Soap bubble, CC BY 2.0, via Wikimedia Commons |
| sodium-cut-lithium-floats-photo | figure | Composite: Nefronus, sodium sample, CC0; Steve Jurvetson, lithium in mineral oil, CC BY 2.0; via Wikimedia Commons; captions added |
| soil | figure | ManuelB701, Nieder-Olm - Maulwurfshuegel an dem Teufelspfad, CC0, via Wikimedia Commons |
| solar-cell-structure | figure | S-kei, vectorised by WYKIWYC, public domain, via Wikimedia Commons |
| solenoid-field-drawn | figure | Chalklet AI Labs, drawn for this project (tools/draw_physics_apparatus.py) - owned |
| special-inflorescences | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| sperm-structure | figure | Mariana Ruiz Villarreal (LadyofHats), Wikimedia Commons, public domain |
| sperm-zona-acrosome | figure | OpenStax, Anatomy and Physiology 2e, section 28.1 Fertilization (Sperm and the Process of Fertilization), CC BY 4.0 |
| sphagnum-moss | figure | National Museum of American History (Smithsonian Institution), via Wikimedia Commons - CC0; cropped 2026-10-15 to remove the museum accession tag |
| sphagnum-peat | figure | NC Wetlands (Sphagnum in Panthertown Valley bog, CC0); David Stanley (Peat, CC BY 2.0); Sphagnum moss in glass bottle (CC0); via Wikimedia Commons, cropped and labelled by Chalklet |
| sphagnum-peat-hyaline | figure | Fred Broerman / USFWS Alaska, elevated sphagnum bog, public domain; Sarah777, peat harvesting in the Bog of Allen, public domain; cell network and moss mat drawn by Chalklet AI Labs |
| spinal-cord-section | figure | OpenStax, Anatomy and Physiology, CC BY 4.0 |
| spinal-frog-reflex | figure | Chalklet AI Labs, drawn for this project (figures/pic2_drawings.py) - owned |
| spinal-nerve-roots | figure | OpenStax, Biology for AP Courses (Figure 35.4.4, spinal cord cross section), CC BY 4.0 as released before 2026-04-23 |
| spongiform-brain-tissue | figure | Dr. Al Jenny, USDA APHIS, public domain |
| sporangium-vs-conidia | figure | Composite: Rhizopus by Agong1, Wikimedia Commons, CC0; Penicillium by Dr Lucille K. Georg, CDC, public domain |
| squid-jet-propulsion | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| stamen-conditions | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| stamen-four-sacs | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| starfish | figure | Flora Mechanica Illustrated Books (FMIB), public domain diagram of the water-vascular system of a starfish, via Wikimedia Commons |
| steel-ball | figure | OpenClips on Pixabay, Shiny steel ball, CC0, via Wikimedia Commons |
| stem-modifications | figure | Pearson Scott Foresman (rhizome, stolon panels, public domain) and Sheila Sund (potato tuber eyes panel, CC BY 2.0), via Wikimedia Commons |
| stem-root-xylem-position | figure | Berkshire Community College Bioscience Image Library, Monocot Stem Vascular Bundle in Zea and Typical Dicot Root Stele in Young Ranunculus, CC0; via Wikimedia Commons, cropped and labelled by Chalklet AI Labs |
| stem-ts | figure | Encyclopaedia Britannica 1911 (Ricinus communis dicot stem panel, public domain) and a cc0 photomicrograph (monocot stem panel), via Wikimedia Commons |
| sterilisation-vasectomy-tubectomy | figure | Ruth Lawson, Otago Polytechnic, Anatomy and Physiology of Animals, CC BY 3.0, via Wikimedia Commons (male ducts, cropped); with CDC, vectorised by Mysid, public domain, via Wikimedia Commons (female); cut-and-tie marks and captions added by Chalklet |
| stomatal-apparatus | figure | via Wikimedia Commons - public domain |
| storage-root-shapes | figure | thebittenword.com (turnip), CC BY 2.0; with Jengod (radish, public domain), Jonathan Pielmayer (carrot, CC0) and Makysm (sweet potato, CC0); all via Wikimedia Commons, cropped and set side by side by Chalklet |
| streptococcus-pneumoniae | figure | CDC/Janice Carr, Public Health Image Library (PHIL 262), via Wikimedia Commons - public domain |
| submarine-photo | figure | U.S. Navy, USS Honolulu (SSN 718) surfaced 280 miles from the North Pole, public domain (US Navy), via Wikimedia Commons |
| sunny-beach-sand-sea-photo | figure | Dan Dan, Sunny Day, CC0, via Wikimedia Commons |
| surrogacy-embryo-transfer | figure | Blausen.com staff (2014), Medical gallery of Blausen Medical 2014, WikiJournal of Medicine 1(2), CC BY 3.0, via Wikimedia Commons; the In Vitro Fertilization and Artificial Insemination plates cropped to their dish and uterus insets and set side by side, with the transfer arrow, the embryo and the labels added by Chalklet (tools/draw_figure_scenes.py) |
| sweet-potato-storage-roots | figure | Makysm, Sweet potato roots, via Wikimedia Commons - CC0 |
| swiss-cheese-holes | figure | Christian Bauer, Wikimedia Commons, CC BY 2.0 |
| sycon-canal-keyed | figure | American Museum of Natural History Guide Leaflet (1901), after Schulze, Internet Archive Book Images, public domain; via Wikimedia Commons, English key added by Chalklet AI Labs |
| sycon-sponge | figure | The American Museum Journal (after Schulze), Internet Archive Book Images, via Wikimedia Commons - public domain |
| sympathetic-innervation | figure | Blausen.com staff (2014). Medical gallery of Blausen Medical 2014. WikiJournal of Medicine 1(2). CC BY 3.0, via Wikimedia Commons; title cropped |
| synovial-joints | figure | OpenStax College, Anatomy and Physiology, Wikimedia Commons, CC BY 3.0 |
| table | figure | Kurtkaiser, Dinner table side pine wood large table side, CC0, via Wikimedia Commons |
| tadpole-frog-excretion | figure | OpenStax, Biology 2e (Figure 15.6.6, photographs modified from Brian Gratwicke), CC BY 4.0 as released before 2026-04-23; panels (a) and (c), with headings and excretory types added by Chalklet |
| tagmata-insect-crustacean | figure | OpenStax, Biology 2e (Figure 28.4.6, bee anatomy, CC BY 4.0 as released before 2026-04-23) and A. N. and D. McAlpine, Biological Atlas (1880), Plate XII (lobster, public domain) |
| tapeworm-life-cycle | figure | OpenStax, Biology 2e (Figure 28.3.3), CC BY 4.0, via Wikimedia Commons |
| tapeworm-scolex-hooks | figure | CDC PHIL 5262, Taenia solium scolex, public domain; via Wikimedia Commons, labelled by Chalklet AI Labs |
| tcell-checks-mhc-peptide | figure | Ryan Kissinger (NIAID), MHC Class II CD4 TCR Complex, NIH BioArt 347, public domain, via Wikimedia Commons, labelled by Chalklet |
| telophase-cell-micrograph | figure | Roy van Heesbeen, public domain, via Wikimedia Commons (TelophaseIF.jpg); cropped and labelled by Chalklet |
| telophase-karyokinesis | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| tendrils-leaf-stem | figure | Jessie Hirsch (pea tendrils, CC BY 2.0), RoRo (Cucurbita maxima shoot, CC0) and Obsidian Soul (Passiflora edulis tendril, CC0); via Wikimedia Commons, set side by side and labelled by Chalklet AI Labs |
| testis-seminiferous-tubules | figure | Neto, Bach, Najafi et al., via Wikimedia Commons - CC BY 4.0 |
| thoracic-cage | figure | OpenStax, Anatomy and Physiology 2e (Figure 7.5.1 b, rib cage), CC BY 4.0; panel (b) only, title and caption by Chalklet |
| thorn-prickle-spine | figure | Bim24 (Bougainvillea, CC0), Alex Abair (Rosa multiflora prickles, CC BY 4.0) and cogdogblog (cactus areoles, CC0); via Wikimedia Commons, set side by side and labelled by Chalklet AI Labs |
| three-sponges | figure | Julien Renoult (Sycon ciliatum, CC BY 4.0), Robert et al. 2022 European Journal of Taxonomy (Spongilla lacustris, Fig. 2 A-B, CC BY 4.0) and EB1911 after F. E. Schulze (Euspongia officinalis, public domain); via Wikimedia Commons, set side by side and labelled by Chalklet AI Labs |
| thylacine-grey-wolf | figure | E.J. Keller and Baker (thylacine, public domain) and Gary Kramer, USFWS (grey wolf, public domain); via Wikimedia Commons, labelled by Chalklet AI Labs |
| thyroid-gland | figure | OpenStax College, Anatomy and Physiology, Wikimedia Commons, CC BY 3.0 |
| tiger-in-forest-photo | figure | Bernard Gagnon, Bengal tiger in Bandhavgarh National Park, CC BY 4.0, via Wikimedia Commons |
| tile | figure | Samiknoov, Brownish floor tiles, CC0, via Wikimedia Commons |
| tmv-mosaic-leaf | figure | R.J. Reynolds Tobacco Company Slide Set, Bugwood.org, Tobacco mosaic virus symptoms on tobacco, CC BY 3.0 US, via Wikimedia Commons, cropped |
| tomato-persistent-calyx | figure | Forest and Kim Starr, via Wikimedia Commons - CC BY 3.0 US; cropped, with the calyx labelled by Chalklet |
| tornaria-bipinnaria | figure | Michael Foster and Francis Maitland Balfour, The Elements of Embryology (tornaria, public domain); Ernst Haeckel, Kunstformen der Natur (Asterias bipinnaria, public domain); via Wikimedia Commons; key letters re-lettered as English labels by Chalklet |
| trachea-c-ring-oesophagus | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py), re-drawn from public-domain plates (see drawn.reference) - owned |
| trachea-cartilage-rings | figure | BruceBlaus (Blausen Medical), Wikimedia Commons, CC BY 3.0 |
| tracheary-differentiation | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| train-coach-photo | figure | Harrison Keely, A coach car aboard Amtrak's Vermonter passenger train, CC BY 4.0, via Wikimedia Commons |
| transgenic-animals | figure | Ingrid Moen and colleagues, BMC Cancer (GFP mice, CC BY 2.0); Keith Weller, USDA (dairy cow, public domain); via Wikimedia Commons, cropped and labelled by Chalklet |
| trex-skeleton-teeth | figure | USDA (USDAgov), Tyrannosaurus rex skeleton in the Smithsonian National Museum of Natural History, public domain, via Wikimedia Commons |
| trichoderma-micrograph | figure | Wikimedia Commons user Arpit, CC0 |
| trichomes-vs-root-hairs | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| trickling-filter-bed-photo | figure | Velela, Trickling filter bed, public domain, via Wikimedia Commons |
| trimerous-pentamerous | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| trna-cloverleaf | figure | DataBase Center for Life Science (DBCLS), via Wikimedia Commons - CC BY 4.0 |
| trypanosoma-tsetse | figure | Composite: Trypanosoma diagram by Peacock, Kay, Bailey and Gibson, CC BY 4.0; tsetse fly by Michael Wunderli, CC BY 2.0; via Wikimedia Commons |
| tunicate-larva-adult | figure | OpenStax, Biology 2e (Figure 29 01 03abc), via Wikimedia Commons - CC BY 4.0; cropped to panels b and c (the photograph removed), the label 'Notocord' re-lettered 'Notochord' |
| tuning-fork-photo | figure | Lukasz Kobus, European Commission, A tuning fork placed on sheet music, CC BY 4.0, via Wikimedia Commons |
| turgid-vs-wilted-stem | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| turmeric-rhizome-and-powder-photo | figure | Nubelbariloe, Picture of turmeric, CC BY 4.0; Trinity Saioo, Lakadong Turmeric Powder final product, CC0; via Wikimedia Commons, composited by Chalklet |
| turtle-tortoise | figure | Michael Lusk, USFWS (green sea turtle, public domain); Adrian Pingstone (spur-thighed tortoise, public domain); via Wikimedia Commons, cropped and labelled by Chalklet |
| typhoid-ileum-perforation | figure | Thomas Godart, typhoid ulceration with perforation of the lower ileum, watercolour, Wellcome Collection, CC BY 4.0, via Wikimedia Commons; caption added |
| underground-stems | figure | OpenStax, Biology 2e (Figure 30 02 10abcdef), via Wikimedia Commons - CC BY 4.0 |
| urea-recycling | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| uric-acid-paste | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| urinary-system | figure | Arcadian, after SEER Training Modules, National Cancer Institute, Wikimedia Commons, public domain |
| vacuum-flask-labelled | figure | Pearson Scott Foresman, Thermos (PSF), public domain (donated to the Wikimedia Foundation), via Wikimedia Commons |
| vascular-bundles | figure | Encyclopaedia Britannica 1911 (Plants - types of stele in vascular plants), via Wikimedia Commons - public domain |
| venturi-pitot-photo | figure | MKFI, Mil Mi-8 pitot tube Torpin Tykit, public domain, via Wikimedia Commons |
| vernier-caliper | figure | Barbarossa at Dutch Wikipedia, Wikimedia Commons, public domain |
| vernier-calliper-photo | figure | Rhetos, vernier calliper measuring the inner diameter of a pipe, CC0, via Wikimedia Commons |
| vertebral-column-26 | figure | OpenStax College, Anatomy and Physiology, Vertebral Column and Vertebra, CC BY 4.0 as released before 2026-04-23; key added by Chalklet AI Labs |
| vertebrate-circulation-compared | figure | OpenStax, Biology 2e (Figure 40.1.3), CC BY 4.0, via Wikimedia Commons |
| viola-oxalis-commelina | figure | Composite: Viola lanceolata, CC0; Oxalis stricta by Cbaile19, CC0; Commelina benghalensis, Herb Pilcher, USDA ARS, public domain; via Wikimedia Commons |
| virus | figure | domdomegg, via Wikimedia Commons - CC BY 4.0 |
| virus-capsid-shapes | figure | OpenStax, Biology 2e (Figure 21.1.2, virus morphology), CC BY 4.0 as released before 2026-04-23 |
| virus-killed-caterpillar-photo | figure | Tucker Lieberman, Gypsy moth caterpillar killed by virus, CC0, via Wikimedia Commons |
| warming-water-bubbles-photo | figure | Tomwsulcer, water in a pot on a stove, CC0, via Wikimedia Commons; caption added |
| watchmaker-and-deadlift-photo | figure | Yilmaz Kilim, Watchmaker, CC0; Sgt. Tara Fajardo Arteaga, U.S. Army, Soldiers Celebrate 4th of July with Sports, public domain; via Wikimedia Commons, composited by Chalklet |
| water-bath | figure | QuodScripsiScripsi, Laboratory water bath, CC0, via Wikimedia Commons |
| water-pollinated-plants | figure | Erasmus Darwin 1789 (Vallisneria spiralis, public domain), USGS (Hydrilla, public domain) and Giselle Blythe (Zostera marina, CC0); via Wikimedia Commons, set side by side and labelled by Chalklet AI Labs |
| water-routes-casparian | figure | Jackacon, vectorised by Smartse, Apoplast and symplast pathways, public domain; via Wikimedia Commons; endodermis panel drawn by Chalklet AI Labs after NCERT |
| wbc-unstained-colourless | figure | Mikael Häggström, via Wikimedia Commons - CC0 |
| wet-scrubber-gas-washer | figure | Robert Forsythe, The Blast Furnace and the Manufacture of Pig Iron (1908), public domain, via Wikimedia Commons |
| whale-calf-and-bat-fur-photo | figure | NOAA Hawaiian Islands Humpback Whale National Marine Sanctuary, Whale And Calf, public domain; NPS Photo, Hoary Bat (Lasiurus cinereus), public domain; via Wikimedia Commons, composited by Chalklet |
| white-blood-cells | figure | Blausen.com staff (2014). Medical gallery of Blausen Medical 2014. WikiJournal of Medicine 1(2). CC BY 3.0, via Wikimedia Commons; cropped, title banner removed |
| widal-test-tray | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| wind-tunnel-photo | figure | U.S. Air Force photo by Jill Pickett, 221122-F-KN521-3032, public domain (US Air Force), via Wikimedia Commons |
| wings-butterfly-bird | figure | Thomas Bresson (Danaus plexippus, CC BY 2.0) and Bengt Nyman (bird in flight, CC BY 2.0); via Wikimedia Commons, labelled by Chalklet AI Labs |
| wurtzite-lattice | figure | Benjah-bmm27, Wikimedia Commons, public domain |
| xray-hand-rontgen | figure | Wilhelm Röntgen, 1896, public domain, via Wikimedia Commons |
| xray-tube-photo | figure | Science Museum London, A 19th century X-ray tube, Wellcome Collection, CC BY 4.0, via Wikimedia Commons |
| xylem-phloem-elements | figure | Chalklet AI Labs, drawn for this project (tools/draw_figure_scenes.py) - owned |
| yeast-saccharomyces | figure | Masur, S. cerevisiae under DIC microscopy, public domain, via Wikimedia Commons, cropped and labelled by Chalklet |
| youngs-modulus-searle-drawn | figure | Chalklet AI Labs, drawn for this project (tools/draw_physics_apparatus.py) - owned |
| zeolite-silicate | figure | François-Xavier Coudert, Wikimedia Commons, CC BY 4.0 |
| zinc-blende-lattice | figure | Benjah-bmm27, Wikimedia Commons, public domain |
| zinc-cofactor-carbonic-anhydrase | figure | Carbonic anhydrase 1CA2 active site, public domain (own work by the uploader), via Wikimedia Commons, labelled by Chalklet |
| zygote-to-implantation | figure | OpenStax, Biology 2e (Figure 43.7.1), CC BY 4.0, via Wikimedia Commons |
| adenovirus | symbol | NIH BioArt Source, National Institutes of Health - public domain |
| antibody | symbol | NIH BioArt Source, National Institutes of Health - public domain |
| arteries-and-veins | symbol | DataBase Center for Life Science (DBCLS), via BioIcons - CC BY 4.0 |
| bacillus | symbol | NIH BioArt Source, National Institutes of Health - public domain |
| bacterium | symbol | Servier Medical Art, via Bioicons - CC BY 3.0 |
| bacterium-interior | symbol | Servier Medical Art, via Bioicons - CC BY 3.0 |
| balance-scale | symbol | Servier Medical Art, via Bioicons - CC BY 3.0 |
| beaker | symbol | DataBase Center for Life Science (DBCLS), via Wikimedia Commons - CC BY 4.0 |
| beaker-of-water | symbol | nUll, via Bioicons - CC0 |
| bone-marrow | symbol | NIH BioArt Source, National Institutes of Health - public domain |
| brain | symbol | Servier Medical Art, via Bioicons - CC BY 3.0 |
| buchner-funnel | symbol | Servier Medical Art, via BioIcons - CC BY 3.0 |
| bunsen-burner | symbol | Servier Medical Art, via Bioicons - CC BY 3.0 |
| burette | symbol | Servier Medical Art, via BioIcons - CC BY 3.0 |
| capillary | symbol | Servier Medical Art, via Bioicons - CC BY 3.0 |
| capillary-network | symbol | Servier Medical Art, via BioIcons - CC BY 3.0 |
| cardiac-muscle-cell | symbol | Servier Medical Art, via Bioicons - CC BY 3.0 |
| carrier-protein | symbol | Servier Medical Art, via BioIcons - CC BY 3.0 |
| cell-membrane | symbol | Servier Medical Art, via Bioicons - CC BY 3.0 |
| centriole | symbol | Servier Medical Art, via Bioicons - CC BY 3.0 |
| chromosomal-inversion | symbol | DataBase Center for Life Science (DBCLS), via BioIcons - CC BY 4.0 |
| chromosome | symbol | NIH BioArt Source, National Institutes of Health - public domain |
| concave-lens | symbol | Steven Legg, via Wikibooks - public domain |
| condenser | symbol | Servier Medical Art, via BioIcons - CC BY 3.0 |
| conical-flask | symbol | DataBase Center for Life Science (DBCLS), via Wikimedia Commons - CC BY 4.0 |
| convex-lens | symbol | Steven Legg, via Wikibooks - public domain |
| dna | symbol | Servier Medical Art, via Bioicons - CC BY 3.0 |
| dna-nucleotides | symbol | Servier Medical Art, via Bioicons - CC BY 3.0 |
| ear-structure | symbol | DataBase Center for Life Science (DBCLS), via BioIcons - CC BY 4.0 |
| eye-section | symbol | Servier Medical Art, via Bioicons - CC BY 3.0 |
| funnel | symbol | SVG Repo, via svgrepo.com - CC0 |
| gap-junction | symbol | Servier Medical Art, via BioIcons - CC BY 3.0 |
| golgi-apparatus | symbol | Servier Medical Art, via Bioicons - CC BY 3.0 |
| gram-negative-wall | symbol | DataBase Center for Life Science (DBCLS), via BioIcons - CC BY 4.0 |
| gram-positive-wall | symbol | DataBase Center for Life Science (DBCLS), via BioIcons - CC BY 4.0 |
| heart | symbol | Servier Medical Art, via Bioicons - CC BY 3.0 |
| heart-section | symbol | Servier Medical Art, via Bioicons - CC BY 3.0 |
| heart-valves | symbol | Servier Medical Art, via BioIcons - CC BY 3.0 |
| horseshoe-magnet | symbol | SVG Repo, via svgrepo.com - CC0 |
| kidney | symbol | Servier Medical Art, via Bioicons - CC BY 3.0 |
| liver | symbol | Servier Medical Art, via Bioicons - CC BY 3.0 |
| lung | symbol | Servier Medical Art, via Bioicons - CC BY 3.0 |
| lymph-node | symbol | DataBase Center for Life Science (DBCLS), via BioIcons - CC BY 4.0 |
| lymphatic-drainage | symbol | Servier Medical Art, via BioIcons - CC BY 3.0 |
| measuring-cylinder | symbol | DataBase Center for Life Science (DBCLS), via Wikimedia Commons - CC BY 4.0 |
| microscope | symbol | DataBase Center for Life Science (DBCLS), via Wikimedia Commons - CC BY 4.0 |
| mitochondrion | symbol | Servier Medical Art, via Bioicons - CC BY 3.0 |
| mortar-and-pestle | symbol | DataBase Center for Life Science (DBCLS), via Wikimedia Commons - CC BY 4.0 |
| motor-neuron | symbol | DataBase Center for Life Science (DBCLS), via BioIcons - CC BY 4.0 |
| neuron | symbol | NIH BioArt Source, National Institutes of Health - public domain |
| nucleosome | symbol | Xi-Chen, via BioIcons - CC0 |
| nucleus | symbol | Servier Medical Art, via BioIcons - CC BY 3.0 |
| pancreas | symbol | Servier Medical Art, via BioIcons - CC BY 3.0 |
| paper-chromatography | symbol | Servier Medical Art, via BioIcons - CC BY 3.0 |
| pipette | symbol | DataBase Center for Life Science (DBCLS), via Wikimedia Commons - CC BY 4.0 |
| plasmid | symbol | EmilyADaniel, via BioIcons - CC0 |
| plasmodium-gametocyte | symbol | Servier Medical Art, via BioIcons - CC BY 3.0 |
| reagent-bottle | symbol | DataBase Center for Life Science (DBCLS), via Wikimedia Commons - CC BY 4.0 |
| red-blood-cell | symbol | Servier Medical Art, via Bioicons - CC BY 3.0 |
| rough-er | symbol | Servier Medical Art, via Bioicons - CC BY 3.0 |
| round-bottom-flask | symbol | DataBase Center for Life Science (DBCLS), via Wikimedia Commons - CC BY 4.0 |
| ruler | symbol | SVG Repo, via svgrepo.com - CC0 |
| screw-gauge | symbol | SVG Repo, via svgrepo.com - CC0 |
| separating-funnel | symbol | Servier Medical Art, via BioIcons - CC BY 3.0 |
| smooth-er | symbol | Servier Medical Art, via Bioicons - CC BY 3.0 |
| spirit-lamp | symbol | DataBase Center for Life Science (DBCLS), via Wikimedia Commons - CC BY 4.0 |
| sporozoites | symbol | Servier Medical Art, via BioIcons - CC BY 3.0 |
| spring | symbol | SVG Repo, via svgrepo.com - CC0 |
| stomach | symbol | Servier Medical Art, via Bioicons - CC BY 3.0 |
| stopwatch | symbol | Servier Medical Art, via Bioicons - CC BY 3.0 |
| telescope | symbol | SVG Repo, via svgrepo.com - CC0 |
| test-tube | symbol | Servier Medical Art, via BioIcons - CC BY 3.0 |
| thermometer | symbol | kehan, via Bioicons - CC0 |
| transformer | symbol | SVG Repo, via svgrepo.com - CC0 |
| translation | symbol | Servier Medical Art, via BioIcons - CC BY 3.0 |
| vernier-caliper | symbol | Joaquim Alves Gaspar, via Wikimedia Commons - CC BY 2.5 |