Biodiversity and species: previous-year questions
73 real UPSC Prelims questions (2011–2026) with the official answer and a clear explanation. 26 of them came in the last five papers.
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Questions per year, counted from the official papers.
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With respect to the Western Hoolock Gibbons, which of the following statements is/are correct ?
- 1. A Sanctuary in North-east India is home to this ape species listed as Endangered in the International Union for Conservation of Nature (IUCN) Red List.
- 2. They have specialized brachiation and can easily swing between trees.
- 3. They possess a strong and heavy build like gorillas, yet are remarkably agile tree climbers.
Select the answer using the code given below :
Answer (b) & explanation
Statements 1 and 2 are correct (b). Statement 1 is right: India's only ape, the western hoolock gibbon, is Endangered on the IUCN Red List and gives its name to the Hollongapar Gibbon Sanctuary in Assam. Statement 2 is right: gibbons move by brachiation, swinging arm over arm through the canopy. Statement 3 is wrong: they are "lesser apes", slim and light, about 6–9 kg, nothing like a heavy gorilla. So options (a), (c) and (d) fail.
Notice their habits: they live in pairs with their young and sing loud duets at dawn. They are found south of the Brahmaputra in the North-East. Rail lines cutting through Hollongapar have raised concern, and canopy bridges were proposed to help them cross.
Answer as per the official UPSC answer key.
Which of the following statements with regard to the arrival of Amur Falcons at Doyang Lake in Nagaland each year from Mongolia is/are correct ?
- 1. It showcases how sustained local conservation efforts can contribute to the arrival and protection of international migratory birds.
- 2. It reflects the global success of advanced tracking technologies that guide migratory birds back to their stopover sites.
- 3. It confirms that Amur Falcons have adapted to permanent residency in India due to favourable habitat changes.
Select the answer using the code given below :
Answer (a) & explanation
Only statement 1 is correct (a). Statement 1 is right: around 2012, villages near Doyang in Nagaland, once known for mass hunting of the birds, turned into protectors, so the falcons now roost safely. Statement 2 is wrong: satellite tags only track the birds; they do not guide them. Statement 3 is wrong: Amur falcons stay only a few weeks, so they are not permanent residents. So options (b), (c) and (d) fail.
Notice their journey: they breed in Mongolia, Siberia and northern China, rest in Nagaland, then cross the Arabian Sea to winter in southern Africa, one of the longest raptor migrations. Pangti village is called the "Falcon Capital of the World". Tagged birds have been named after these villages.
Answer as per the official UPSC answer key.
Consider the following statements about Rhynchostylis retusa (Foxtail orchid) :
- 1. It is an epiphytic orchid.
- 2. The species is endemic to North-east India.
- 3. It is the State flower of Arunachal Pradesh and Assam.
Which of the statements given above is/are correct ?
Answer (b) & explanation
Statements 1 and 3 are correct (b). Statement 1 is right: the foxtail orchid grows on tree trunks and branches, using the tree only for support, so it is epiphytic, not a parasite. Statement 3 is right: it is the State flower of Arunachal Pradesh and of Assam, where it is the kopou phool, worn in Bihu dances. Statement 2 is wrong: it is not endemic; it grows across South and South-East Asia. So options (a), (c) and (d) fail.
Notice the North-East's orchid wealth: Arunachal alone has over 600 orchid species, and Sikkim's state flower, the Noble Dendrobium, is also an orchid. The Tipi Orchid Research Centre is in Arunachal. All wild orchids trade under CITES Appendix II.
it is famous in the North-east, but "endemic" means found nowhere else.
Answer as per the official UPSC answer key.
Regarding Peacock tarantula (Gooty tarantula), consider the following statements :
- I. It is an omnivorous crustacean.
- II. Its natural habitat in India is only limited to some forest areas.
- III. In its natural habitat, it is an arboreal species.
Which of the statements given above is/are correct?
Answer (d) & explanation
Statements II and III are correct (d). Statement II is right: the peacock tarantula (Gooty tarantula) is found only in a few forest patches of the Eastern Ghats, mainly in Andhra Pradesh. Statement III is right: it lives in tree holes, so it is arboreal. Statement I is wrong: it is a spider, an arachnid, not a crustacean, and it eats insects, not plants. So options (a), (b) and (c) fail.
Notice its status: it is Critically Endangered on the IUCN Red List, mainly due to deforestation and the pet trade, valued for its bright blue colour. It is named after Gooty town, where it was first found. Its bite is painful but rarely dangerous.
"crustacean" sounds scientific. Spiders are arachnids; crabs and prawns are crustaceans.
Answer as per the official UPSC answer key.
Consider the following statements :
- Statement-I : The Indian Flying Fox is placed under the “vermin” category in the Wild Life (Protection) Act, 1972.
- Statement-II : The Indian Flying Fox feeds on the blood of other animals.
Which one of the following is correct in respect of the above statements ?
No official answer (question dropped) & notes
UPSC dropped this question, so no answer was counted. The facts are still worth knowing. Statement II is wrong: the Indian flying fox is a large fruit bat; it eats fruit and nectar, not blood. It helps pollinate flowers and spread seeds. Statement I was the problem: the bat was listed as vermin in Schedule V of the 1972 Act, but the 2022 amendment removed the vermin schedule altogether, cutting the schedules to four. That change made Statement I unclear, and the question was dropped.
Notice that only three bat species in the world feed on blood, the vampire bats of Latin America. Fruit bats came into the news during Nipah virus outbreaks in Kerala, since they carry the virus naturally.
UPSC did not evaluate this question, so no official answer exists. Use it for practice only.
UPSC dropped this question from evaluation; there is no official answer.
The organisms “Cicada, Froghopper and Pond skater” are :
Answer (c) & explanation
All three are insects (c). Cicadas are known for their loud summer calls, made by males to attract mates; some species spend 13 or 17 years underground as young. Froghoppers, or spittlebugs, are known for the frothy "cuckoo spit" their young make on plants to hide in, and the adults are among the best jumpers in the animal world. Pond skaters, or water striders, walk on water using surface tension and water-repelling hairs on their legs. None of them is a bird (a), fish (b) or reptile (d).
Notice the shared trait: all three are true bugs (Hemiptera), with mouthparts made for sucking plant sap or prey fluids. Like all insects, they have six legs and three body parts.
Answer as per the official UPSC answer key.
Consider the following pairs :
| Country | Animal found in its natural habitat
| 1. Brazil | Indri
| 2. Indonesia | Elk
| 3. Madagascar | Bonobo
How many of the pairs given above are correctly matched ?
Answer (d) & explanation
None of the pairs is correctly matched (d). UPSC shuffled the pairs. Pair 1 is wrong: the indri, the largest living lemur, is found only in Madagascar, not Brazil. Pair 2 is wrong: elk are large deer of the northern forests of North America and Eurasia, not tropical Indonesia. Pair 3 is wrong: the bonobo, a great ape close to the chimpanzee, lives only in the DR Congo, south of the Congo river, not Madagascar.
Notice the theme of endemism: species found in only one place. Madagascar split from Africa and India long ago, so about 90% of its wildlife, including all lemurs, is found nowhere else. Indonesia's famous endemics are the Komodo dragon and the orangutan.
Madagascar and a great ape sound plausible together. Madagascar has lemurs, but no apes.
Answer as per the official UPSC answer key.
Consider the following statements :
- 1. Lions do not have a particular breeding season.
- 2. Unlike most other big cats, cheetahs do not roar.
- 3. Unlike male lions, male leopards do not proclaim their territory by scent marking.
Which of the statements given above are correct ?
Answer (a) & explanation
Statements 1 and 2 are correct (a). Statement 1 is right: lions have no fixed breeding season; they can mate at any time of the year, and lionesses in a pride often give birth around the same time. Statement 2 is right: cheetahs cannot roar, unlike lions, tigers, leopards and jaguars; they purr, chirp and hiss, because their voice box is built differently. Statement 3 is wrong: male leopards do mark their territory, by spraying urine, scraping trees and leaving scat, just as lions do.
Notice India's link: Project Cheetah brought African cheetahs to Kuno National Park, Madhya Pradesh, in 2022, the first intercontinental move of a large wild carnivore. The Asiatic lion survives only in Gir, Gujarat.
Answer as per the official UPSC answer key.
Consider the following :
- 1. Butterflies
- 2. Fish
- 3. Frogs
How many of the above have poisonous species among them ?
Answer (c) & explanation
All three have poisonous species (c). Item 1 is right: monarch butterflies store toxins from the milkweed plants they eat as caterpillars, so birds that eat them get sick; their bright colours warn predators. Item 2 is right: pufferfish carry tetrodotoxin, a deadly nerve poison; in Japan, only licensed chefs may prepare it as fugu. Item 3 is right: the bright poison dart frogs of South America are among the most toxic animals on Earth; tribes used their poison on darts.
Notice the term aposematism: bright warning colours that advertise poison. Some harmless species copy them, called Batesian mimicry. Note the difference: poisonous animals harm you when eaten or touched, while venomous animals, such as snakes, inject toxin.
Answer as per the official UPSC answer key.
Consider the following :
- 1. Cashew
- 2. Papaya
- 3. Red sanders
How many of the above trees are actually native to India ?
Answer (a) & explanation
Only one of them is native to India (a). Item 3 is right: red sanders (Pterocarpus santalinus) is native to India, found only in the southern Eastern Ghats of Andhra Pradesh, especially the Seshachalam hills. It is Endangered because of heavy smuggling for its deep red wood, prized in China and Japan. Item 1 is wrong: cashew came from Brazil. Item 2 is wrong: papaya came from Central America. Both were brought to India by the Portuguese in the 16th century.
Notice other crops the Portuguese brought: chilli, potato, tomato, tobacco, pineapple and groundnut, all from the Americas. Today India is a top producer of cashew and the largest producer of papaya. Red sanders is also listed in CITES Appendix II.
cashew and papaya are so common in India that they feel native.
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Answer as per the official UPSC answer key.
Consider the following :
- 1. Carabid beetles
- 2. Centipedes
- 3. Flies
- 4. Termites
- 5. Wasps
Parasitoid species are found in how many of the above kind of organisms ?
Answer (b) & explanation
Parasitoids are found in three of the five (b). A parasitoid lives in or on a host as a larva, feeds on it and finally kills it, unlike a true parasite, which usually keeps its host alive. Most parasitoids are wasps (item 5) and flies (item 3), such as tachinid flies. A few carabid (ground) beetles (item 1) have parasitoid larvae. Item 2 is wrong: centipedes are predators. Item 4 is wrong: termites feed on dead wood and plant matter.
Notice their use in farming: parasitoid wasps such as Trichogramma are released to control crop pests like the sugarcane borer and cotton bollworm. This biological control cuts the need for chemical pesticides and is part of integrated pest management.
Answer as per the official UPSC answer key.
Consider the following plants :
- 1. Groundnut
- 2. Horse-gram
- 3. Soybean
How many of the above belong to the pea family ?
Answer (c) & explanation
All three belong to the pea family (c). The pea family, Fabaceae or the legumes, bears seeds in pods and has root nodules, where Rhizobium bacteria fix nitrogen from the air. Groundnut (item 1) is a legume, though it ripens its pods underground. Horse-gram (item 2) is a hardy pulse grown in dry areas of the south. Soybean (item 3) is a legume, even though, like groundnut, it is used mainly as an oilseed in India. So options (a), (b) and (d) are wrong.
Notice why legumes matter: they enrich the soil with nitrogen, so farmers rotate or intercrop them with cereals. India is the world's largest producer and consumer of pulses. 2016 was the UN's International Year of Pulses.
groundnut is sold as a "nut" and an oilseed, but botanically it is a legume.
Answer as per the official UPSC answer key.
‘Invasive Species Specialist Group’ (that develops Global Invasive Species Database) belongs to which one of the following organizations?
Answer (a) & explanation
The ISSG belongs to the IUCN (a). The Invasive Species Specialist Group is one of the specialist groups of the IUCN Species Survival Commission, the same body behind the Red List. It runs the Global Invasive Species Database, which lists alien species that harm native life. Option (b) is wrong: UNEP runs global environment programmes but not this group. Option (c) is wrong: the World Commission on Environment and Development (Brundtland Commission) gave the 1987 report on sustainable development. Option (d) is wrong: WWF is a separate conservation NGO.
Notice India's major invasive species: Lantana, Parthenium (congress grass), water hyacinth and Prosopis juliflora. The Kunming-Montreal framework (2022) aims to cut the arrival of invasive species by half by 2030.
Answer as per the official UPSC answer key.
Consider the following fauna :
- 1. Lion-tailed Macaque
- 2. Malabar Civet
- 3. Sambar Deer
How many of the above are generally nocturnal or most active after sunset?
Answer (a) & explanation
Only one of them is nocturnal (a). The Malabar civet, a critically endangered and possibly extinct animal of the Western Ghats, is active at night, like most civets. Item 1 is wrong: the lion-tailed macaque, also of the Western Ghats, is active by day, like most monkeys. Item 3 is treated as wrong: UPSC's key regards the sambar as feeding mainly around dawn and dusk rather than through the night, though it does turn nocturnal where hunted.
Notice the terms: nocturnal (night), diurnal (day) and crepuscular (dawn and dusk). Animals active at night often have big eyes, a sharp sense of smell or good hearing. The lion-tailed macaque is endangered, found only in rainforest canopies of Kerala, Karnataka and Tamil Nadu.
Answer as per the official UPSC answer key.
Which of the following organisms perform waggle dance for others of their kin to indicate the direction and the distance to a source of their food?
Answer (c) & explanation
Honeybees perform the waggle dance (c). A forager honeybee that finds food returns to the hive and does a figure-of-eight waggle dance on the comb. The angle of the waggle run, measured from straight up, shows the direction of the food relative to the Sun. The length of the run shows the distance. Other bees follow the dance and fly to the spot. Butterflies (a), dragonflies (b) and wasps (d) do not communicate this way.
Notice that Karl von Frisch decoded the dance and won the Nobel Prize in 1973. Bees matter far beyond honey: they pollinate many crops. India's National Beekeeping and Honey Mission pushes the Sweet Revolution.
Answer as per the official UPSC answer key.
Consider the following statements :
- 1. Some mushrooms have medicinal properties.
- 2. Some mushrooms have psycho-active properties.
- 3. Some mushrooms have insecticidal properties.
- 4. Some mushrooms have bioluminescent properties.
How many of the above statements are correct?
Answer (d) & explanation
All four statements are correct (d). Mushrooms are the fruiting bodies of fungi, and they are very varied. Statement 1 is right: reishi, shiitake and cordyceps are used in traditional and modern medicine. Statement 2 is right: "magic mushrooms" contain psilocybin, which acts on the mind; it is now being tested for depression. Statement 3 is right: some fungi make chemicals that kill insects, and others are used as biopesticides. Statement 4 is right: a few species glow in the dark through bioluminescence, including some found in the Western Ghats.
Notice the link with livelihoods: India promotes mushroom farming as a low-land, high-income crop, and the Gucchi mushroom of Kashmir has a GI tag.
Answer as per the official UPSC answer key.
Consider the following statements regarding the Indian squirrels :
- 1. They build nests by making burrows in the ground.
- 2. They store their food materials like nuts and seeds in the ground.
- 3. They are omnivorous.
How many of the above statements are correct?
Answer (b) & explanation
Two statements are correct (b). Statement 1 is wrong: Indian squirrels, such as the palm squirrel and the giant squirrel, build nests in trees, in holes or of twigs and leaves, not burrows in the ground. Statement 2 is right: they bury nuts and seeds to eat later, a habit called caching. Forgotten caches often sprout, so squirrels help spread trees. Statement 3 is right: they are omnivorous, eating insects, eggs and even small birds as well as fruits, seeds and flowers.
Notice the Indian giant squirrel (Malabar giant squirrel), the state animal of Maharashtra, and the Grizzled giant squirrel, which has a sanctuary at Srivilliputhur in Tamil Nadu. Ground squirrels that do burrow, like marmots, are a different group.
Answer as per the official UPSC answer key.
Consider the following statements :
- 1. Some microorganisms can grow in environments with temperature above the boiling point of water.
- 2. Some microorganisms can grow in environments with temperature below the freezing point of water.
- 3. Some microorganisms can grow in highly acidic environment with a pH below 3.
How many of the above statements are correct?
Answer (c) & explanation
All three statements are correct (c). These microbes are extremophiles. Statement 1 is right: some archaea near deep-sea vents grow above 100°C; water stays liquid there because of high pressure. Methanopyrus kandleri grows at up to 122°C. Statement 2 is right: psychrophiles grow below 0°C in sea ice, glaciers and permafrost, where salt keeps water liquid. Statement 3 is right: acidophiles live in acid mine water and hot springs with a pH near 1.
Notice the uses: the enzyme Taq polymerase, from a hot-spring bacterium, made the PCR test possible, which was used for COVID testing. Extremophiles also suggest where life might exist on other worlds, such as Mars or Jupiter's moon Europa.
Answer as per the official UPSC answer key.
Which one of the following makes a tool with a stick to scrape insects from a hole in a tree or a log of wood?
Answer (b) & explanation
The orangutan uses a stick as a tool (b). Orangutans, especially in Sumatra, shape sticks to pry insects and honey out of tree holes and to break open spiny fruits. Young ones learn the skill from their mothers, a sign of culture in apes. Option (d) is the trap: the sloth bear eats termites and ants, but it sucks them out of mounds through a gap in its front teeth; it makes no tool. The fishing cat (a) catches fish with its paws. Otters (c) use stones to crack shells but do not dig insects with sticks.
Notice the famous tool-users: chimpanzees "fish" for termites with stems, crows bend wires into hooks, and Egyptian vultures drop stones on eggs. Orangutans are critically endangered by palm oil plantations.
the sloth bear is famous for eating termites, which makes it tempting.
Answer as per the official UPSC answer key.
‘Aerial metagenomics’ best refers to which one of the following situations?
Answer (a) & explanation
Aerial metagenomics means collecting DNA from the air at one go (a). Animals and plants constantly shed tiny bits of DNA into the air, through skin, hair, pollen and spores. Aerial metagenomics filters air at one spot and reads all the DNA at once to list the species present, without seeing or catching them. It is part of environmental DNA (eDNA) methods. Option (b) is too narrow: it is not limited to birds. Option (c) is wrong: it does not take blood from animals. Option (d) describes drone sampling of land and water.
Notice that in 2022, scientists picked up DNA of animals in a zoo just by sampling the air. eDNA from water is already used to track fish and rare species.
"aerial" suggests birds or drones, but it refers to the air sample.
Answer as per the official UPSC answer key.