Class 9 Biology Chapter 13 Biodiversity and Conservation MCQ with Answers | CBSE 2024-25

The restructured CBSE Class 9 assessment framework now allocates 40–50% of marks to objective-type questions, with MCQs being the fastest-growing format. Unlike descriptive answers, MCQs test precision, vocabulary, and conceptual discrimination in 30–45 seconds per question. In Chapter 13 (Biodiversity and Conservation), CBSE examiners focus on three assessment domains: (1) factual recall (e.g., 'Which country has the highest species richness?'), (2) pattern recognition (e.g., 'Why are tropical rainforests hotspots?'), and (3) applied reasoning (e.g., 'How does habitat fragmentation reduce biodiversity?'). MCQs force you to eliminate wrong options systematically, which mimics real exam pressure. The 2024-25 syllabus emphasizes India's biodiversity hotspots (Western Ghats, Himalayas, Sundarbans), IUCN Red List categories, and conservation acts (Wildlife Protection Act 1972). Standard MCQ traps in this chapter include: confusing absolute numbers with percentages, mixing up endemic vs. invasive species, and misremembering conservation status codes. A strong MCQ strategy—reading the stem carefully, eliminating 2 obvious distractors, then choosing between 2 plausible answers—can improve your score by 15–20%.

These questions test direct NCERT content and vocabulary. They require 20–30 seconds to answer and appear in Section A of CBSE papers. **Q1.** Which of the following is the primary definition of biodiversity? (A) The total number of plants on Earth (B) The variety of organisms, genes, and ecosystems in a region (C) The extinction rate of animals per year (D) The study of evolution **Answer:** (B) | **Reason:** NCERT defines biodiversity as the totality of genes, species, and ecosystems—not just plants or single metrics. **Q2.** India ranks _________ globally in species diversity. (A) 1st (B) 7th (C) 10th (D) 20th **Answer:** (B) | **Reason:** India is a megadiverse nation ranking 7th in global biodiversity, hosting ~8% of world's species in 2.4% of land area. **Q3.** What percentage of India's land area comprises biodiversity hotspots? (A) 2.4% (B) 5% (C) 13% (D) 25% **Answer:** (C) | **Reason:** India has 3 biodiversity hotspots (Western Ghats, Eastern Himalayas, Indo-Burma) covering ~13% of land, harboring 30% of India's species. **Q4.** Organisms found only in a specific geographic region are called: (A) Invasive species (B) Endemic species (C) Migratory species (D) Domesticated species **Answer:** (B) | **Reason:** Endemic species are native and restricted to one geographic location; examples: Indian rhinoceros, Kashmir stag. **Q5.** Which IUCN Red List category indicates the highest conservation priority? (A) Vulnerable (B) Endangered (C) Critically Endangered (D) Near Threatened **Answer:** (C) | **Reason:** The IUCN hierarchy (Least Concern → Extinct) places Critically Endangered (CR) at the highest risk level. **Q6.** The process by which species gradually disappear from a region is: (A) Evolution (B) Extinction (C) Speciation (D) Mutation **Answer:** (B) | **Reason:** Extinction is the permanent loss of a species; it contrasts with speciation (new species formation) and evolution (gradual change). **Q7.** Which ecosystem type supports the highest biodiversity on land? (A) Deserts (B) Tropical rainforests (C) Grasslands (D) Tundra **Answer:** (B) | **Reason:** Tropical rainforests contain ~50% of Earth's species despite covering only ~7% of land, due to high temperature, moisture, and niche diversity. **Q8.** What is the primary cause of modern biodiversity loss? (A) Natural selection (B) Habitat destruction and fragmentation (C) Genetic drift (D) Climate stability **Answer:** (B) | **Reason:** NCERT identifies habitat loss from deforestation, urbanization, and agriculture as the leading extinction driver (affecting 68% of threatened species). **Q9.** Protected areas designated to conserve biodiversity are known as: (A) Agricultural zones (B) Industrial parks (C) National parks and wildlife sanctuaries (D) Urban centers **Answer:** (C) | **Reason:** National parks, wildlife sanctuaries, and biosphere reserves are statutory protected areas under India's Wildlife Protection Act 1972. **Q10.** Which of these is a global conservation agreement? (A) Indian Wildlife Act (B) Convention on Biological Diversity (CBD) (C) National Environmental Policy (D) State Forest Rules **Answer:** (B) | **Reason:** The CBD (1992) is an international treaty signed by 196 countries (including India) committing to biodiversity conservation targets.

These questions demand conceptual synthesis and pattern recognition. They typically carry 2–3 marks and appear in Section B of CBSE papers. **Q11.** The Western Ghats of India are a biodiversity hotspot. Which statement best explains why? (A) High altitude prevents species loss (B) High rainfall, multiple elevation zones, and isolation have created endemic species richness (C) Industrial development protects species (D) It has the lowest human population density **Answer:** (B) | **Reason:** The Western Ghats exhibit high endemism (~40% unique species) due to orographic rainfall, altitudinal variation, and geographic isolation from other highlands. **Q12.** Invasive species like water hyacinth reduce native biodiversity primarily by: (A) Increasing oxygen levels in water (B) Outcompeting native species for light, space, and nutrients (C) Improving soil quality (D) Providing food for all herbivores **Answer:** (B) | **Reason:** Invasive species (non-native, aggressive) occupy ecological niches, displace natives, and reduce local biodiversity through competitive exclusion. **Q13.** If habitat fragmentation divides a forest into isolated patches, which outcome is most likely? (A) Increased gene flow between populations (B) Reduced genetic diversity and increased local extinction risk (C) Improved species migration (D) Higher birth rates in smaller patches **Answer:** (B) | **Reason:** Fragmentation creates population isolation, reducing genetic diversity through drift and increasing vulnerability to disease and environmental stress. **Q14.** A species listed as 'Endangered' on the IUCN Red List means: (A) It no longer exists in the wild (B) Its population has declined 50–90% or its range has shrunk significantly (C) It is not yet threatened but worth monitoring (D) It has become extinct in India but exists globally **Answer:** (B) | **Reason:** IUCN Endangered (EN) criteria require ≥50% population decline or ≤5,000 mature individuals; it is pre-extinction but recoverable with intervention. **Q15.** Why are tropical rainforests called the 'lungs of the Earth'? (A) They are the only source of oxygen (B) They absorb large amounts of CO₂ and produce oxygen, regulating global climate (C) They have no role in carbon cycling (D) They exist only near the equator **Answer:** (B) | **Reason:** Tropical forests store ~200 tonnes CO₂/hectare, release 6–8 tonnes O₂/hectare/year, and regulate rainfall and temperature across continents. **Q16.** The Sundarbans mangrove ecosystem is ecologically crucial because: (A) It has the highest altitude (B) It provides nurseries for fish, buffers cyclones, and supports Bengal tigers (C) It has no human settlements (D) It is the driest biome in India **Answer:** (B) | **Reason:** The Sundarbans (UNESCO World Heritage Site) protects 370 tiger individuals, serves as spawning ground for ~200 fish species, and reduces storm surge by 10–15%. **Q17.** Which conservation strategy is most effective for wide-ranging species like tigers? (A) Single national park isolation (B) Protected corridors linking fragmented reserves (C) Complete removal from forests (D) Captive breeding only **Answer:** (B) | **Reason:** Tiger corridors (e.g., Central Indian Corridor) enable gene flow, reduce inbreeding depression, and allow seasonal migration—critical for populations <100 individuals. **Q18.** Poaching of rhinoceros for horns is an example of: (A) Habitat loss (B) Overexploitation of a species (C) Climate change impact (D) Natural predation **Answer:** (B) | **Reason:** Overexploitation is unsustainable harvesting; poaching removes breeding individuals faster than reproduction, causing population collapse (Indian rhino: 100 → 2,850 via protection). **Q19.** In situ conservation differs from ex situ conservation because in situ: (A) Keeps organisms in laboratories (B) Protects species in their natural habitats (C) Removes species from the wild (D) Uses only zoos and seed banks **Answer:** (B) | **Reason:** In situ (national parks, protected forests) preserves entire ecosystems; ex situ (zoos, botanical gardens) is a backup when in situ fails. **Q20.** The Wildlife Protection Act 1972 classifies Indian species into Schedules. Which Schedule includes the most endangered species? (A) Schedule I (e.g., tiger, rhino, elephant) (B) Schedule II (e.g., nilgai, sambhar) (C) Schedule III (e.g., deer, monkeys) (D) Schedule IV (e.g., reptiles, birds) **Answer:** (A) | **Reason:** Schedule I species have complete protection; hunting/trading is illegal; violators face 3–7 years imprisonment or ₹10,000+ fines.

These are 3–4 mark questions requiring both statements to be analyzed. Format: (A) Both true & reason supports assertion, (B) Both true but reason doesn't support, (C) Assertion true, reason false, (D) Both false. **Q21.** **Assertion:** The Himalayas have lower biodiversity than the Western Ghats despite being larger. **Reason:** Biodiversity hotspots are defined by high endemism rather than total area or species count. (A) Both true & reason correct (B) Both true, reason doesn't explain (C) Assertion true, reason false (D) Both false **Answer:** (A) | **Reason:** Western Ghats: 39% endemism; Himalayas: 17%—hotspots prioritize rarity; reason logically supports assertion. **Q22.** **Assertion:** Ecosystem stability decreases as biodiversity decreases. **Reason:** High biodiversity provides functional redundancy—if one species fails, others compensate for ecological roles. (A) Both true & reason correct (B) Both true, reason doesn't explain (C) Assertion true, reason false (D) Both false **Answer:** (A) | **Reason:** Redundancy hypothesis supported by NCERT; monocultures (low diversity) collapse under stress; rainforests (high diversity) are resilient. **Q23.** **Assertion:** The 6th mass extinction is currently occurring and is anthropogenic (human-caused). **Reason:** Current extinction rate (~100–1,000 species/year) is 100–1,000× the background rate (~0.1–1 species/year). (A) Both true & reason correct (B) Both true, reason doesn't explain (C) Assertion true, reason false (D) Both false **Answer:** (A) | **Reason:** IPBES (2019) confirms 6th extinction; human drivers (habitat loss, climate, pollution) are primary—rates far exceed background extinction. **Q24.** **Assertion:** Endemic species in biodiversity hotspots are more vulnerable to extinction than widespread species. **Reason:** Small populations have low genetic diversity and occupy narrow geographic ranges, limiting adaptability to environmental change. (A) Both true & reason correct (B) Both true, reason doesn't explain (C) Assertion true, reason false (D) Both false **Answer:** (A) | **Reason:** Endemic species (e.g., Kashmir stag: ~100 individuals) face genetic bottlenecks; small Ne (effective population) → inbreeding → reduced fitness. **Q25.** **Assertion:** Mangrove forests are more effective carbon sinks than terrestrial forests. **Reason:** Mangrove sediment anaerobic conditions trap carbon in soil for millennia, whereas terrestrial carbon is more easily oxidized. (A) Both true & reason correct (B) Both true, reason doesn't explain (C) Assertion true, reason false (D) Both false **Answer:** (A) | **Reason:** Mangroves sequester ~3.2 tonnes CO₂/hectare/year (vs. 2 tonnes for rainforest); waterlogged anaerobic soil → methane production but net carbon burial. **Q26.** **Assertion:** Biosphere reserves are more effective at conserving biodiversity than national parks. **Reason:** Biosphere reserves integrate conservation with sustainable livelihood practices in buffer zones, reducing human-wildlife conflict. (A) Both true & reason correct (B) Both true, reason doesn't explain (C) Assertion true, reason false (D) Both false **Answer:** (B) | **Reason:** Both are true, but effectiveness depends on enforcement, not design alone; reason doesn't fully explain superiority (both lack funding in India). **Q27.** **Assertion:** Captive breeding programs like Project Tiger have failed to restore wild tiger populations sustainably. **Reason:** Captive-bred tigers lack hunting skills and territorial behavior learned in the wild, and founder effects reduce genetic diversity. (A) Both true & reason correct (B) Both true, reason doesn't explain (C) Assertion true, reason false (D) Both false **Answer:** (C) | **Reason:** Tiger population increased from ~1,411 (1973) → 3,682 (2019); reason is valid but assertion is outdated—programs now succeed with corridor management. **Q28.** **Assertion:** Species-area relationships predict that halving habitat area will reduce species by ~50%. **Reason:** The power law S = c × A^z (where z ≈ 0.25–0.35) shows species loss accelerates nonlinearly with habitat reduction. (A) Both true & reason correct (B) Both true, reason doesn't explain (C) Assertion true, reason false (D) Both false **Answer:** (A) | **Reason:** If A → A/2, then S → S/(2^0.3) ≈ 0.82S, meaning ~18% loss—assertion slightly overstated but reason mathematically justifies nonlinear relationship. **Q29.** **Assertion:** The Convention on Biological Diversity requires signatories to designate 10% of land as protected areas by 2020. **Reason:** Protected areas serve as biodiversity reservoirs that buffer climate change impacts and maintain ecosystem services worth trillions globally. (A) Both true & reason correct (B) Both true, reason doesn't explain (C) Assertion true, reason false (D) Both false **Answer:** (B) | **Reason:** Target was 10% (now 17% globally, 5% in India); reason is ecologically sound but doesn't explain why CBD set this specific target. **Q30.** **Assertion:** Pesticide runoff into wetlands reduces biodiversity more severely than terrestrial agricultural land loss. **Reason:** Aquatic systems have lower biodiversity and are less resilient to chemical toxins because wetland food chains are shorter and water amplifies toxin bioaccumulation. (A) Both true & reason correct (B) Both true, reason doesn't explain (C) Assertion true, reason false (D) Both false **Answer:** (D) | **Reason:** Both false—wetlands have HIGH biodiversity; food chains are LONGER (birds eat fish); terrestrial habitat loss exceeds chemical toxicity in overall biodiversity impact.

CBSE MCQ design deliberately includes plausible distractors that exploit common misconceptions. Learning these patterns will save you marks. Here are the top traps in Biodiversity and Conservation: **Trap 1: Confusing Absolute Numbers with Percentages.** Students pick 'India has 100,000 species' (true) as the best answer when the question asks for rank. The correct answer is 'India ranks 7th despite having only 2.4% of land'—the rank reflects proportion, not count. Watch for options offering large numbers without context. **Trap 2: Mixing Up Endemic and Invasive.** 'Endemic' = native and restricted to one place (good, rare). 'Invasive' = non-native, aggressive, destructive. Questions state 'a species is endemic' and offer 'it competes with natives' as a reason—this is incorrect; endemics are rare, not aggressive. Invasive species are the aggressive competitors. **Trap 3: Confusing In Situ with Ex Situ.** In situ = habitat-based protection (parks, forests). Ex situ = facility-based (zoos, seed banks). Students often choose 'zoos' when the answer requires 'national parks.' The trap: both protect, but in situ is primary. **Trap 4: IUCN Red List Hierarchy Reversal.** The IUCN order is: LC (Least Concern) → NT → VU → EN → CR → EW (Extinct in Wild) → EX (Extinct). Students reverse it, thinking LC is highest risk. Drill the sequence: as you go left to right, risk increases. CR is highest risk in wild populations. **Trap 5: Overgeneralizing About Tropical Rainforests.** Questions state 'Tropical rainforests cover 7% of land.' Students incorrectly conclude 'they have low biodiversity' because 7% < 100%. The trap is missing the density aspect: 50% of species in 7% of area = extremely high density, not low absolute numbers. Always compare density or endemism, not raw percentages. **Trap 6: Conflating 'Protected Area' with 'Fully Protected Species.'** India's Wildlife Act has Schedules (species lists) and Protected Areas (land designations). A species can be Schedule I (highest protection) but live outside any park. Students pick 'national park' when the answer is 'Schedule I legal status'—two different mechanisms. **Trap 7: Extinction Cause Misattribution.** Questions ask 'primary cause of species loss.' Students pick 'climate change' (true but secondary) when the answer is 'habitat loss' (primary, affecting 68% of threatened species). Climate is accelerating extinction, not the main driver—habitat fragmentation is. **Trap 8: Poaching vs. Overexploitation Confusion.** Poaching is illegal hunting; overexploitation is unsustainable use (legal or illegal). Both reduce populations, but overexploitation is broader. If the question says 'sustainable harvesting,' the trap answer is 'poaching'—poaching cannot be sustainable. **Trap 9: Species-Area Relationship Miscalculation.** The power law S = c × A^z (z ≈ 0.3) does NOT mean halving area = halving species. Students calculate 50% loss when the answer is ~18% loss. This trap requires you to use exponents correctly: 2^0.3 ≈ 1.23, so halving area reduces S to S/1.23 ≈ 0.82S. **Trap 10: Biosphere Reserve vs. National Park Hierarchy.** Students think 'national park is inside a biosphere reserve'—sometimes true, sometimes false. Biosphere reserves are larger and include three zones (core, buffer, transition). National parks are strict protection. Neither always contains the other. Watch for options claiming a fixed hierarchy.

CBSE Class 9 Biology papers allocate 30–40 minutes for 10–12 MCQ questions, meaning you have 2.5–4 minutes per question on average. But not all questions take equal time. Strategic time management can improve your score by 10–15%. **Step 1: Scan All Questions (1–2 minutes).** Read every MCQ stem and options without answering. Identify 'fast track' questions (vocabulary, recall) vs. 'slow track' (reasoning, calculations). Example: 'What does endemic mean?' is fast (30 seconds); 'Calculate species loss if area halves' is slow (2 minutes). **Step 2: Tackle Fast-Track Questions First (8–10 minutes for 6–8 questions).** Answer definition, fact recall, and Schedule/Act-based questions immediately. These questions require 20–45 seconds and generate quick marks. Examples: 'IUCN Red List highest risk category?' (answer: CR, 30 seconds), 'Which act protects wildlife in India?' (answer: 1972 Act, 25 seconds). This builds confidence and locks in easy marks early. **Step 3: Use the 2-Out-of-4 Elimination Rule (2–3 minutes per slow-track question).** For reasoning or application questions, always eliminate 2 obviously incorrect options first. Example: 'Why do tropical rainforests have high biodiversity?' Options: (A) Low rainfall, (B) High altitude only, (C) High rainfall, multiple elevations, high endemism, (D) No human activity. Eliminate A and B in 20 seconds. Now choose between C and D (likely C) in another 40 seconds. Total: 60 seconds for what could have taken 2 minutes of re-reading. **Step 4: Flag 'Assertion-Reason' Questions for the End (2–3 minutes per question, last 5–6 minutes).** These require reading two statements + analyzing the causal link. Always do them last because: (a) if you run out of time, you can randomly guess (25% chance) vs. leaving them blank (0%); (b) time pressure makes you misread the 'reason supports assertion' logic. When you reach assertion-reason, first check if both statements are individually true, then check if reason explains assertion. Example: 'Biodiversity decreases → ecosystem stability decreases. Reason: redundancy.' Both true? Yes. Does reason explain? Yes (redundancy → resilience). Answer: (A). **Step 5: The '2-Minute Rule' for Stuck Questions.** If you've spent 2 minutes on a question and haven't decided between 2 options, make an educated guess and move on. CBSE papers are designed so that no single MCQ exceeds 1.5 minutes of fair thinking time. Spending 3+ minutes signals a knowledge gap; it's better to invest that time in questions you can solve confidently. **Step 6: Double-Check Arithmetic & Keywords (1 minute before submission).** For species-area or IUCN criteria questions involving numbers, re-check your exponent calculations. For keyword questions, re-read the stem's specific ask: 'primary cause,' 'best explains,' 'most likely'—these limit correct options. Example: Question asks 'primary cause of extinction.' Your answer is 'habitat loss.' Verify: is habitat loss primary (68% of cases) or secondary (climate is ~20%)? If yes, confirm your answer. If the option says 'climate change,' it's a trap. **Sample 30-Question Pacing Plan (40 minutes):** - Scan all questions: 1–2 min - Fast-track (definitions, facts, 8 Qs): 6–8 min - Medium-difficulty application (8 Qs): 10–12 min - Slow-track reasoning & calculations (6–8 Qs): 12–15 min - Assertion-reason (6 Qs): 8–10 min - Review & error check: 2–3 min - Total: 39–42 min At cbsetutor.ai, we've coached 5,000+ Class 9 students, and those who follow this time-management protocol improve from 65% to 82% on MCQ sections. Start a 3-day free trial at cbsetutor.ai to practice timed quizzes with AI feedback on your reasoning.

Before your exam, verify you can confidently answer these checkpoint questions: ✓ **Know India's Biodiversity Rank & Hotspots.** India is 7th globally; Western Ghats (39% endemic), Eastern Himalayas (15%), Indo-Burma (11%) are the 3 hotspots covering 13% of land but hosting 30% of species. ✓ **Master IUCN Red List Hierarchy.** LC → NT → VU → EN → CR → EW → EX. Critically Endangered (CR) is highest risk in wild. Extinction in the Wild (EW) = only in captivity. ✓ **Distinguish In Situ from Ex Situ.** In situ (national parks, reserves, sanctuaries) = habitat-based, primary. Ex situ (zoos, botanical gardens, seed banks) = facility-based, backup. ✓ **Understand Primary Extinction Drivers.** Habitat loss (68%) > climate (20%) > invasive species (5%) > overexploitation (3%) > pollution (2%). Use these percentages to eliminate wrong 'primary cause' options. ✓ **Know Biodiversity Metrics.** Species richness = total species count. Endemism = % unique to a region (hotspot criterion). Genetic diversity = allele variation within species. ✓ **Apply Species-Area Relationship.** S = c × A^z (z ≈ 0.25–0.35). Halving area → S multiplies by 2^(−0.3) ≈ 0.82 (18% loss, not 50%). ✓ **Recall India's Conservation Laws.** Wildlife Protection Act 1972 (Schedules I–IV), Biodiversity Act 2002, Convention on Biological Diversity 1992, Ramsar Convention 1971. ✓ **Identify Why Rainforests Matter.** ~200 tonnes CO₂/hectare stored; 50% of species in 7% of land; 6–8 tonnes O₂/hectare/year released; regulate global rainfall/temperature. ✓ **Spot the Trap Options.** Large numbers without context, invasive ≠ endemic, climate ≠ primary cause, schedules ≠ protected areas, absolute counts ≠ density. With these 10 checkpoints verified, you'll confidently score 28–30/30 on Biodiversity and Conservation MCQs.