Complete answer key for the NEET 2026 Biology section. Use the quick-reference grid to spot-check your answers, then drop into the chapter-grouped solutions to understand each question. Pair this with our NEET 2026 Biology paper analysis for the strategic picture.
Tap any number to find the chapter-grouped solution below. Answers are option numbers as released in the NEET 2026 paper.
Solutions are grouped by NCERT chapter so you can revise the matching PYQ set after every mock.
| Q No. | Ans | Key concept & brief solution |
|---|---|---|
| Q104 | 4 | Binomial nomenclature The first word denotes the genus and the second denotes the specific epithet. The statement reversing this is the incorrect one. |
| Q132 | 3 | Five Kingdom Classification (Whittaker, 1969) Whittaker's main criteria were cell structure, body organisation, mode of nutrition, reproduction and phylogenetic relationships — A, B, D and E. Presence of flagellum was not a primary criterion. |
| Q No. | Ans | Key concept & brief solution |
|---|---|---|
| Q92 | 2 | Gymnosperms — exposed ovules Gymnosperms have ovules not enclosed by an ovary wall. Among the options, Pinus is a gymnosperm. |
| Q No. | Ans | Key concept & brief solution |
|---|---|---|
| Q146 | 4 | Sexual dimorphism in frogs Male frogs are distinguished by vocal sacs (B) and a copulatory pad on the first digit of the forelimbs (D). Bulging eyes, webbed digits and olive-green skin with dark spots are common to both sexes. |
| Q147 | 2 | Cyclostomes — Petromyzon Petromyzon has a cartilaginous endoskeleton, circular sucking mouth, no scales/paired fins, and 6–15 pairs of gill slits — matching all three observed characters. |
| Q153 | 4 | Class Osteichthyes (bony fishes) Flying fish (Exocoetus), Angel fish (Pterophyllum) and Fighting fish (Betta) are all bony fishes. Devil fish/cuttlefish are molluscs; hagfish is a cyclostome; sawfish/dogfish are cartilaginous; starfish is an echinoderm. |
| Q154 | 2 | Phylum-level features Adult echinoderms show radial symmetry (B is incorrect); reptiles are cold-blooded and cannot maintain a constant body temperature (E is incorrect). |
| Q166 | 4 | Frog anatomy Hepatic portal system links liver and intestine (A ✓); ureters and oviducts open separately into the cloaca in females (C ✓); sinus venosus joins the right atrium (E ✓). Frogs have 10 pairs of cranial nerves and the midbrain — not hindbrain — has the optic lobes. |
| Q179 | 3 | Aptenodytes (penguin) Penguins are flightless birds with forelimbs modified into flippers (paddle-like structures) for swimming. Struthio (ostrich) is flightless but uses forelimbs for balance, not swimming. |
| Q No. | Ans | Key concept & brief solution |
|---|---|---|
| Q91 | 4 | Region of maturation — root hairs Root hairs are formed from epidermal cells in the region of maturation, which lies above the elongation zone. |
| Q118 | 2 | Solanaceae floral formula Solanaceae shows actinomorphic, bisexual, pentamerous, gamosepalous, gamopetalous, epipetalous flowers with bicarpellary syncarpous superior ovary — option (2). |
| Q121 | 4 | Racemose inflorescence In racemose inflorescence the main axis continues to grow and flowers are borne laterally in acropetal succession. Cymose inflorescence terminates in a flower. |
| Q131 | 1 | Placentation types Marginal — Pea; Axile — Lemon; Parietal — Mustard; Basal — Marigold. |
| Q No. | Ans | Key concept & brief solution |
|---|---|---|
| Q99 | 4 | Bulliform cells Bulliform cells are large, empty colourless cells; on water loss they become flaccid and curl the leaf inwards, minimising water loss during stress. |
| Q113 | 3 | Vascular and ground tissues Conjunctive tissue lies between xylem and phloem; Casparian strips are suberin deposits on endodermal cells; subsidiary cells flank guard cells; starch sheath is the starch-rich endodermis. |
| Q No. | Ans | Key concept & brief solution |
|---|---|---|
| Q106 | 3 | Nucleolus — rRNA synthesis Active ribosomal RNA synthesis occurs in the nucleolus. |
| Q155 | 1 | Ribosomes Ribosomes are non-membrane-bound organelles found in both prokaryotes and eukaryotes. |
| Q175 | 4 | Cell organelles B, C, D are correct. The endomembrane system does NOT include mitochondria (A wrong); mitochondrion is a double-membrane organelle (E wrong). |
| Q176 | 3 | Plasma membrane A, B and D correct. Mesosomes (C) are prokaryotic; glycocalyx (E) lies on the prokaryotic outer cell envelope, not the typical eukaryotic plasma membrane. |
| Q No. | Ans | Key concept & brief solution |
|---|---|---|
| Q101 | 4 | Phases of cell cycle G1 — metabolically active, no DNA replication; S — DNA synthesis (DNA doubles); G2 — protein synthesis with continued growth; M — actual cell division. |
| Q No. | Ans | Key concept & brief solution |
|---|---|---|
| Q98 | 1 | Protein structure — α-helix α-helix (right-handed helix) is a feature of secondary structure of proteins. |
| Q123 | 2 | Biomolecule classification B, C and E are correct. Lipids are not water soluble (A wrong); adenine and guanine are substituted purines, not pyrimidines (D wrong). |
| Q126 | 3 | Amino acid classification Amino acids are substituted methanes (A ✓); valine is neutral (C ✓). Serine is an alcoholic (not aromatic) amino acid; lysine is basic (not acidic). |
| Q133 | 1 | Bioactive molecule categories Trypsin — Enzyme; Morphine — Alkaloid; Concanavalin A — Lectin; Collagen — Intercellular ground substance. |
| Q141 | 3 | Enzyme class — Lyases Lyases catalyse removal of groups from substrates by mechanisms other than hydrolysis, leaving double bonds (X-C-C-Y → X-Y + C=C). |
| Q No. | Ans | Key concept & brief solution |
|---|---|---|
| Q111 | 4 | Photosynthesis — incorrect statements Water-splitting complex is associated with PS-II (A wrong); Kranz anatomy is a C4, not C3, feature (D wrong). B, C and E are correct. |
| Q116 | 3 | Calvin cycle — RuBisCO RuBP carboxylase-oxygenase (RuBisCO) catalyses CO₂ fixation in the Calvin cycle. |
| Q117 | 1 | ATP & NADPH for one glucose Each Calvin turn fixes 1 CO₂ using 3 ATP + 2 NADPH. Six turns are needed for one glucose ⇒ 18 ATP and 12 NADPH. |
| Q No. | Ans | Key concept & brief solution |
|---|---|---|
| Q107 | 1 | Respiratory Quotient (RQ) RQ = CO₂ released / O₂ consumed = 102 / 145 ≈ 0.7 — characteristic of fats; lies between 0.5 and 0.95. |
| Q128 | 3 | Locations within the cell Glycolysis — cytoplasm; ETS — inner mitochondrial membrane; proton accumulation — intermembrane space; Krebs cycle — mitochondrial matrix. |
| Q No. | Ans | Key concept & brief solution |
|---|---|---|
| Q114 | 4 | Phase of elongation Elongation is marked by new wall deposition, vacuolation and enlargement. Large conspicuous nuclei characterise the meristematic phase. |
| Q115 | 1 | Plant growth regulators 2,4-D — Herbicide; GA₃ — Brewing industry; Kinetin — Nutrient mobilisation; ABA — Stomatal closure. |
| Q125 | 4 | Plasticity The ability of plants to follow different developmental pathways in response to environment (e.g., heterophylly) is plasticity. |
| Q No. | Ans | Key concept & brief solution |
|---|---|---|
| Q122 | 2 | Microsporogenesis sequence Sporogenous tissue (B) → Pollen mother cells (D) → Microspore tetrads (A) → Pollen grains (C). |
| Q129 | 4 | Triploid Primary Endosperm Cell Synergid is haploid; zygote diploid; central cell becomes 2n after polar nuclei fusion; only the Primary Endosperm Cell (after triple fusion) is triploid. |
| Q130 | 2 | Xenogamy Xenogamy — pollen transfer from anther of one plant to stigma of a different plant — is the only type that brings genetically different pollen to the stigma. |
| Q No. | Ans | Key concept & brief solution |
|---|---|---|
| Q108 | 1 | Patterns of inheritance Incomplete dominance — Antirrhinum; Co-dominance — ABO blood groups; Pleiotropy — Phenylketonuria; Polygenic — Human skin colour. |
| Q124 | 1 | Honeybee sex determination A, B, C, E are correct. Males are haploid (16 chromosomes) versus diploid females (32). Males produce sperms by mitosis (so D is wrong). |
| Q135 | 2 | Sickle-cell anaemia Caused by substitution of Glu by Val at position 6 of the β-globin chain — autosomal recessive. |
| Q143 | 1 | Blood group probability Cross IᴬI × IᴮI gives IᴬIᴮ : Iᴬi : Iᴮi : ii = AB : A : B : O. Probability of O = 25%. |
| Q160 | 1 | Sickle-cell mutant codon Single base substitution changes the 6th β-globin codon from GAG (Glu) to GUG (Val), causing HbS polymerisation and sickling. |
| Q168 | 3 | Grasshopper XX-XO sex determination Males are XO (one X, here 23 chromosomes); females are XX (24 chromosomes). So 23 = male, 24 = female. |
| Q169 | 1 | Haploid gametes by mitosis Male honeybees are haploid and produce sperms by mitosis (haplodiploid system). |
| Q No. | Ans | Key concept & brief solution |
|---|---|---|
| Q93 | 3 | lac operon — z gene In the lac operon the z gene encodes β-galactosidase (y → permease, a → transacetylase). |
| Q103 | 4 | Transcription unit features All five statements (A–E) accurately describe a transcription unit: promoter, structural gene, terminator; promoter at 5′ end, defines template/coding strand; terminator at 3′ end of coding strand. |
| Q110 | 1 | DNA packaging — histones A, C, E correct. Histones are positively (not negatively) charged basic proteins (B wrong); DNA is negatively (not positively) charged (D wrong). |
| Q No. | Ans | Key concept & brief solution |
|---|---|---|
| Q145 | 3 | Convergent vs divergent evolution Forelimbs of whales and bats are homologous structures showing divergent evolution — not convergent. |
| Q148 | 4 | Chronology of life forms 65 mya — Dinosaurs disappear; 500 mya — Invertebrates appear; 350 mya — Jawless fish; 320 mya — Seaweeds and a few plants. |
| Q178 | 1 | Human evolution sequence Ramapithecus → Homo habilis → Homo erectus → Neanderthal → Homo sapiens. |
| Q No. | Ans | Key concept & brief solution |
|---|---|---|
| Q163 | 2 | Spermatogenesis C ✓ (secondary spermatocytes undergo 2nd meiotic division to form haploid spermatids); E ✓ (spermatids → spermatozoa via spermiogenesis). A, B, D are incorrect. |
| Q167 | 2 | Foetal development timeline 8 wk — limbs and digits; 12 wk — major organ systems and external genitalia; 20 wk — first foetal movement and head hair; 24 wk — fine body hair, separated eyelids and eyelashes. |
| Q170 | 3 | Layers around female gamete Outer to inner: Corona radiata → Zona pellucida → Perivitelline space → Plasma membrane of ovum. |
| Q No. | Ans | Key concept & brief solution |
|---|---|---|
| Q149 | 1 | Contraceptive devices Progestasert — Hormone-releasing IUD; Multiload 375 — Copper-releasing IUD; Diaphragm — Female rubber barrier; Saheli — Oral contraceptive. |
| Q174 | 4 | GIFT (Gamete Intra Fallopian Transfer) GIFT transfers an ovum from a donor into the fallopian tube of a female who cannot produce one but can support fertilisation and development. |
| Q No. | Ans | Key concept & brief solution |
|---|---|---|
| Q139 | 1 | Plasmodium life cycle Mosquito injects sporozoites (E) → reach liver via blood (D) → asexual multiplication in liver cells (B) → asexual multiplication in RBCs (A) → gametocytes form in RBCs (C). |
| Q151 | 3 | Drugs of abuse Nicotine → adrenal catecholamine release; Morphine → sedative/painkiller (opioid); Heroin → depressant; Cocaine → stimulant, euphoria. |
| Q No. | Ans | Key concept & brief solution |
|---|---|---|
| Q150 | 2 | WBC differential count Eosinophils ≈ 2–3% of 8000 = 160–240/cu mm; Lymphocytes ≈ 20–25% of 8000 = 1600–2000/cu mm. |
| Q157 | 3 | Rh grouping & erythroblastosis foetalis Erythroblastosis foetalis arises when the mother is Rh⁻ᵛᵉ and foetus is Rh⁺ᵛᵉ (A reversed); anti-Rh antibodies are administered to the mother after the FIRST (not second) child (E wrong). |
| Q No. | Ans | Key concept & brief solution |
|---|---|---|
| Q138 | 3 | Respiration steps in humans Pulmonary ventilation (C) → Alveolar gas diffusion (B) → Transport by blood (E) → Tissue diffusion (A) → Cellular respiration (D). |
| Q144 | 1 | Respiratory volumes ERV — 1000–1100 mL; RV — 1100–1200 mL; IRV — 2500–3000 mL; TV — 500 mL. |
| Q159 | 1 | Modes of respiration across taxa Molluscs — Branchial; Reptiles — Pulmonary only; Adult amphibians — Pulmonary + cutaneous; Amoeba — Cellular respiration. |
| Q No. | Ans | Key concept & brief solution |
|---|---|---|
| Q137 | 4 | Renin–Angiotensin pathway Fall in GFR (C) → Renin acts; Angiotensinogen → Ang I → Ang II (E) → Vasoconstriction & aldosterone release (D) → Na⁺/H₂O reabsorption (B) → BP and GFR rise (A). |
| Q164 | 4 | Juxta Glomerular Apparatus JGA forms at the contact between the distal convoluted tubule and the afferent arteriole. |
| Q No. | Ans | Key concept & brief solution |
|---|---|---|
| Q142 | 4 | Synaptic transmission Receptors for neurotransmitters reside on the post-synaptic membrane. |
| Q No. | Ans | Key concept & brief solution |
|---|---|---|
| Q136 | 3 | Hormone actions Cortisol — anti-inflammatory; Aldosterone — Na⁺/H₂O reabsorption at renal tubules; Cholecystokinin — pancreatic enzyme & bile secretion; Progesterone — alveolar formation in mammary glands. |
| Q No. | Ans | Key concept & brief solution |
|---|---|---|
| Q161 | 4 | Muscle contraction A, B, D, E correct. C is wrong — Ca²⁺ binds troponin and removes the masking of myosin-binding sites, ACTIVATING (not inactivating) actin for cross-bridge formation. |
| Q162 | 2 | Human endoskeleton B, C, E correct. Human skull is dicondylic (A wrong); ALL human ribs (not all except last 2 pairs) are bicephalic (D wrong). |
| Q177 | 1 | Muscle/skeletal disorders Tetany — wild contractions due to low Ca²⁺; Arthritis — joint inflammation; Myasthenia gravis — autoimmune NMJ disorder; Muscular dystrophy — progressive skeletal muscle degeneration. |
| Q No. | Ans | Key concept & brief solution |
|---|---|---|
| Q95 | 1 | Biotech tools and sources GMO — Bt cotton; Thermostable DNA polymerase — Thermus aquaticus; Ti plasmid — Agrobacterium tumefaciens; pBR322 — E. coli. |
| Q100 | 4 | PCR steps Each PCR cycle: Denaturation → Annealing → Extension. |
| Q109 | 3 | DNA fingerprinting sequence Isolation & RE digestion (A) → Electrophoresis (E) → Transfer to membrane (C) → Hybridisation with VNTR probe (B) → Autoradiography (D). |
| Q112 | 1 | Somatic hybridisation Isolate single cells (D) → Digest cell walls (A) → Isolate naked protoplasts (B) → Fuse to get hybrid protoplast (C) → Grow into a new plant (E). |
| Q120 | 4 | Restriction endonucleases C is wrong — they cut slightly AWAY from the centre of the palindrome; D is wrong — removing nucleotides from ends is the function of exonucleases. A, B, E are correct. |
| Q134 | 2 | DNA gel electrophoresis & visualisation DNA is cut by restriction enzymes (A ✓), separated by size on agarose gel (B ✓). Fragments cannot be seen without staining; ethidium-bromide-stained DNA fluoresces under UV (not visible) light. |
| Q140 | 3 | pBR322 selection markers BamHI site lies within the tetracycline-resistance gene of pBR322. Insertion at BamHI causes loss of tetracycline resistance only. |
| Q No. | Ans | Key concept & brief solution |
|---|---|---|
| Q152 | 1 | α-1-antitrypsin Human α-1-antitrypsin from transgenic animals is used to treat emphysema. |
| Q172 | 1 | Bt toxin specificity cryIAc / cryIIAb proteins control cotton bollworms; cryIAb controls corn borer. Match: cryIAc (cotton bollworms) and cryIAb (corn borer). |
| Q No. | Ans | Key concept & brief solution |
|---|---|---|
| Q158 | 4 | Bioactive industrial molecules Streptokinase — clot buster; Statins (Monascus purpureus) — cholesterol-lowering; Lipases — detergent formulations; Cyclosporin A (Trichoderma polysporum) — immunosuppressant. |
| Q171 | 1 | Swiss Cheese holes Large holes in Swiss cheese are caused by abundant CO₂ produced by Propionibacterium sharmanii. |
| Q No. | Ans | Key concept & brief solution |
|---|---|---|
| Q156 | 2 | Verhulst-Pearl logistic growth dN/dt = rN[(K − N)/K], where K = carrying capacity, r = intrinsic rate of natural increase, N = population density. |
| Q165 | 2 | Sexual deceit Ophrys orchid mimics a female bumblebee, exploiting pseudocopulation for pollination — classic sexual deceit. |
| Q180 | 3 | Population interactions B, D, E correct. In commensalism only one species benefits, the other is unaffected (so C is wrong). Parasitism: one benefits, one harmed; amensalism: one harmed, one unaffected. |
| Q No. | Ans | Key concept & brief solution |
|---|---|---|
| Q96 | 1 | Productivity definitions Productivity — rate of biomass production; NPP — GPP minus respiration losses; GPP — rate of photosynthetic organic matter production; Secondary productivity — rate of new organic matter formation by consumers. |
| Q105 | 2 | Decomposition processes Decomposition — breakdown of complex organic matter; Detritus — dead remains/faecal matter; Mineralisation — release of inorganic nutrients; Humification — accumulation of dark amorphous humus. |
| Q173 | 4 | Inverted ecological pyramids Pyramid of biomass in the sea is inverted (small phytoplankton biomass supports larger consumer biomass). The other three pyramids in the options are upright. |
| Q No. | Ans | Key concept & brief solution |
|---|---|---|
| Q94 | 3 | Bioprospecting Bioprospecting — exploring molecular, genetic and species-level diversity for products of economic importance. |
| Q97 | 3 | Sixth mass extinction Current extinction rates are 100 to 1000 times faster than pre-human times — the sixth episode is in progress. |
| Q102 | 2 | Causes of biodiversity loss A, B, D correct. Nile perch CAUSED extinction of cichlid fish (C wrong); when a species goes extinct, associated species are affected via co-extinctions (E wrong). |
| Q119 | 1 | In-situ conservation Sacred Groves are an in-situ conservation example. Wildlife safari parks, botanical gardens and seed banks are ex-situ. |
| Q127 | 3 | Evil Quartet The four major causes of biodiversity loss: Habitat loss & fragmentation, Over-exploitation, Alien species invasions, and Co-extinctions. |
The answer to Q91 in NEET 2026 Biology is option (4) — the region of maturation. Root hairs in angiosperms arise from the region of maturation of the root, where some epidermal cells form fine, delicate, thread-like extensions called root hairs.
MedicNEET hosts the complete NEET 2026 Biology answer key for Q91–Q180 with brief NCERT-based solutions on this page. Solutions are grouped chapter-wise so you can revise alongside the relevant PYQ set after every mock test.
The full NEET 2026 Biology answer key spans Q91 to Q180 (90 questions, 360 marks). The complete option-by-option list and brief explanations for each answer are available on this page, including chapter-grouped solutions and a quick-reference grid of all 90 answers.
The MedicNEET app has 10,000+ chapter-wise questions in the new NEET 2026 format — long-form Statement-Based and 4×4 Match-the-Column.
The NEET 2026 Biology section runs from Q91 to Q180 — 90 questions, 360 marks. The official pattern shifted decisively in 2026: zero Assertion-Reason questions, 18 Match-the-Column items, 29 Statement-Based items and 43 Direct/Standard MCQs. For the verified counts and the strategic implications, see our NEET 2026 Biology paper analysis.
This answer key is structured for revision rather than first-time learning. Use the quick-reference grid to mark your mock against the actual paper, then drop into the chapter-grouped solutions to read a one-line concept reminder plus the brief NCERT-based reasoning. Each chapter card links to the corresponding chapter-wise PYQ set on MedicNEET — the right next step after marking your mock is to drill the chapters where you lost marks, not to re-read NCERT cover to cover.
For NEET 2027 candidates: practising in the new long-form Statement-Based format is more important than additional content coverage. Roughly one in three NEET 2026 Biology questions was a long-form Statement-Based item (4 or 5 sub-statements per question), and partial knowledge in this format earns zero marks. Use the chapter weightage data and our important topics list to prioritise the chapters that contributed most heavily to the 2026 paper.