Biodiversity, Protected Areas and Habitats

• Pair 1 is correctly matched. The Nokrek Biosphere Reserve lies in the Garo Hills of Meghalaya, taking its name from Nokrek peak, the highest point of the Garo Hills, and it is known for the wild citrus gene pool, Citrus indica, which is the reason for its designation.
• Pair 2 is wrongly matched. Loktak Lake is in the Manipur valley near Imphal, famous for its floating phumdis and for Keibul Lamjao, the only floating national park in the world and the last refuge of the sangai. The Barail Range is the highest range in Assam, lying on the Assam Nagaland border and separating the Barak valley from the rest of Assam, well to the west of Loktak.
• Pair 3 is wrongly matched. Namdapha National Park is in Changlang district in the extreme east of Arunachal Pradesh, in the Patkai and Mishmi hills near the Myanmar border, and is celebrated as the only protected area in the world holding four large cats, tiger, leopard, snow leopard and clouded leopard. The Dafla Hills, associated with the Nyishi, lie in western Arunachal Pradesh, at the opposite end of the State. The official answer (a), one only, follows. The elimination route is Loktak, which is the best known of the three and is unambiguously a Manipur valley lake, and defeating pair 2 removes options (b) and (c) at once, after which only pair 1 has to be adjudicated.

• Pair 1 is wrongly matched. The river flowing through Corbett is the Ramganga, on which the Kalagarh reservoir stands within the park, together with the Kosi along its eastern boundary. The Ramganga is a tributary of the Ganga, but the Ganga itself does not flow through the park, and the question asks for the river flowing through it.
• Pair 2 is wrongly matched. Kaziranga lies on the southern bank of the Brahmaputra in the Golaghat and Nagaon districts of Assam, and the rivers within it are the Diphlu, the Mora Diphlu and the Mora Dhansiri, with the Brahmaputra forming its northern boundary. The Manas flows through Manas National Park, some distance to the north west, and the pairing is a straightforward transposition between two Assam parks.
• Pair 3 is wrongly matched. Silent Valley in Palakkad district of Kerala is drained by the Kunthipuzha, a tributary of the Bharathapuzha, and the entire park lies within that catchment. The Kaveri rises in Kodagu and drains eastward across Karnataka and Tamil Nadu, on the other side of the divide. All three failing, the official answer is (d). The elimination route is Silent Valley, whose association with the Kunthipuzha is inseparable from the hydroelectric project that the Silent Valley movement of the late nineteen seventies defeated; recognising that removes options (b) and (c), and the Kaziranga and Manas transposition removes (a).

• Statement 1 is correct. Equatorial rainforest is defined by its stratification, with emergents rising above a closed canopy at roughly thirty to forty five metres whose interlocking crowns intercept most of the incident light, an understorey adapted to deep shade, and a forest floor that is comparatively open because so little light reaches it.
• Statement 2 is correct and is the best known property of the biome: species richness per hectare is the highest of any terrestrial system, with hundreds of tree species in a single hectare and no dominance by one or two, which is why commercial exploitation of a single timber species is difficult there. The standard explanations are the constancy of the climate, the absence of a limiting season and the long evolutionary continuity of the habitat.
• Statement 3 is correct. Epiphytes, orchids, bromeliads, ferns and mosses growing on the trunks and branches of other plants without parasitising them, are abundant precisely because light is the scarce resource on the floor and humidity is high throughout the canopy, so growing on a host is the efficient way to reach the light. Lianas and buttress roots belong to the same suite of adaptations. All three being correct, the official answer is (d).

• Pair 1 is correctly matched. Dampa Tiger Reserve lies in the Mamit district of western Mizoram along the Bangladesh border and is that State's largest protected area, notified as a tiger reserve in 1994.
• Pair 2 is incorrectly matched. The Gumti Wildlife Sanctuary is in Tripura, in the Gomati river catchment, and is known for its elephant and avifaunal populations; it has no connection with Sikkim, whose protected areas are Khangchendzonga, Fambong Lho, Maenam, Barsey Rhododendron, Kyongnosla and Shingba.
• Pair 3 is correctly matched. Saramati, at about three thousand eight hundred and forty metres, is the highest peak of Nagaland, standing on the border with Myanmar in the Naga Hills. The official answer is therefore (c). The item is decided on pair 2. Sikkim is a Himalayan State whose protected area names are almost all Tibetan or Lepcha in derivation, whereas Gumti is a Tripura river name, and that linguistic mismatch alone is enough to reject the pair, which removes (b) and (d). Dampa is the more commonly known of the remaining two, so a candidate confident of it reaches (c) without needing to place Saramati.

• Statement 1 is correct. Dams and barrages fragment the river into isolated stretches, block the seasonal movements on which the species depends, and alter the flow and depth regime; the Farakka barrage is the standard Indian example, having divided the Ganges population and reduced dry season flows downstream.
• Statement 2 is incorrect. Crocodilian populations in the Ganges system have declined rather than increased, the gharial being critically endangered, and in any case the gharial is a specialised fish eater that is not a significant predator of dolphins. This is the planted statement.
• Statement 3 is correct. Accidental capture in gillnets is among the largest direct sources of mortality; the animal is functionally blind, navigating by echolocation, and monofilament nylon nets return a poor acoustic signal, so entanglement is common.
• Statement 4 is correct. Agricultural runoff brings organochlorine and organophosphate residues and nutrient loads into the river; the dolphin is a long-lived apex predator and accumulates persistent lipophilic compounds through biomagnification, with effects on reproduction and immunity, while nutrient enrichment depletes dissolved oxygen. The official answer is (c). The elimination is clean and single-step: statement 2 is the only implausible item in the set, and (c) is the only option that omits it.

• Pair 1 is correctly matched. The Harike wetland in Punjab was formed by the construction of a barrage in 1953 at the confluence of the Beas and the Sutlej, and is a Ramsar site and an important waterfowl wintering ground.
• Pair 2 is incorrectly matched. Keoladeo Ghana National Park at Bharatpur is a man-made and man-managed wetland created in the eighteenth century by the ruler of Bharatpur as a duck shooting reserve, fed by the Gambhir and Banganga rivers through the Ajan Bund; it does not lie at any confluence, and the Banas joins the Chambal far to the south in Sawai Madhopur district.
• Pair 3 is incorrectly matched. Kolleru Lake in Andhra Pradesh is a shallow freshwater lake lying between the deltas of the Krishna and the Godavari, fed by the Budameru and the Tammileru and connected to the sea by the Upputeru; it is not a confluence of the Musi and the Krishna, those two rivers meeting near Wazirabad in Telangana. The official answer is (a).
• Pair 1 is the securely known one, so the practical route is to confirm it and then treat pairs 2 and 3 with suspicion, since both attach a river confluence to a wetland whose water source is well known to be something else.

• Option (a) is correct, and the words together with traditional human life are the whole of the question. A biosphere reserve under the UNESCO Man and the Biosphere Programme is zoned into a core, which is legally protected and left undisturbed, a buffer, where research, education and non-destructive activity are permitted, and a transition or manipulation zone, where human settlements, agriculture and sustainable resource use continue. It is the only one of the four designations that is designed to reconcile conservation with the continued presence and livelihood of resident communities, and to treat traditional knowledge as an asset rather than an intrusion.
• Option (c) is incorrect: a national park under the Wild Life (Protection) Act, 1972 is the most strictly protected category, in which grazing and rights are extinguished.
• Option (d) is incorrect: a wildlife sanctuary permits certain regulated rights but its object is species and habitat protection rather than the maintenance of a human cultural landscape.
• Option (b) is incorrect and is out of category altogether, a botanical garden being a form of ex-situ conservation, maintaining plants outside their natural habitat, whereas the question is asking about in-situ conservation of a living landscape.

• Option (b) is correct. Keibul Lamjao in Manipur, on the southern part of Loktak Lake, is the only floating national park in the world, its surface formed of phumdis, mats of decomposing vegetation, soil and organic matter, and it is the last natural habitat of the sangai or brow antlered deer.
• Option (a) is wrong: Bhitarkanika in Odisha is a mangrove ecosystem in the Brahmani Baitarani delta, known for the saltwater crocodile.
• Option (c) is wrong: Keoladeo Ghana at Bharatpur is a man made shallow freshwater wetland famous for migratory waterfowl, but its vegetation is rooted, not floating.
• Option (d) is wrong: Sultanpur in Haryana is a small shallow lake bird sanctuary raised to national park status. The single word that decides the item is floating, which is unique to the phumdi ecosystem.

• Option (d) is correct. The Andaman and Nicobar Islands carry all three formations within a small area: extensive mangrove along the tidal creeks, most famously at Baratang and in the Middle Andaman, tropical wet evergreen forest in the interior of the high rainfall islands, and moist deciduous forest with Andaman padauk on the drier and more disturbed tracts. High rainfall, an equable maritime climate and a broken tidal coastline are what allow the three to sit together.
• Option (a) is wrong: north coastal Andhra Pradesh has mangrove in the Godavari and Krishna deltas and moist to dry deciduous forest inland, but no true tropical evergreen forest.
• Option (b) is wrong: the Sundarbans mangrove lies in the south of West Bengal, and the state's forests are otherwise sal deciduous, evergreen forest being confined to the far north in the Terai and Dooars foothills rather than to the south west, whose Jangalmahal tract is dry deciduous.
• Option (c) is wrong: southern Saurashtra is a semi arid tract with thorn and scrub forest and small mangrove patches in the Gulf of Kachchh, and Gir is dry deciduous. The elimination route is the requirement of evergreen forest, which needs rainfall above about 2000 millimetres and eliminates three of the four regions at once.

• Option (d) is correct. Namdapha National Park in Changlang district of Arunachal Pradesh rises from about 200 metres on the Noa-Dihing to 4571 metres at Dapha Bum, a vertical span of more than four kilometres within a single protected area, so its vegetation runs continuously from tropical evergreen through subtropical and temperate broadleaf and conifer forest to alpine meadow and permanent snow. It is also the only protected area in the world recorded as holding four large cats, the tiger, common leopard, clouded leopard and snow leopard, which is a direct consequence of that altitudinal range.
• Option (a) is wrong: Khangchendzonga in Sikkim reaches far greater absolute height but begins at about 1800 metres, so its lower limit is subtropical to temperate and it has no tropical belt.
• Option (b) is wrong for the same reason: Nanda Devi begins around 1800 metres in the Garhwal Himalaya.
• Option (c) is wrong: Neora Valley in the Kalimpong hills of West Bengal spans roughly 180 to 3200 metres, reaching temperate forest but not the permanent snow zone. The governing principle is that the question is really about amplitude of relief rather than about absolute altitude, and the park that starts lowest and finishes highest wins.

• Option (a) is correct. Teak, Tectona grandis, is the characteristic dominant of the tropical moist deciduous formation, which occupies areas receiving roughly 100 to 200 centimetres of annual rainfall with a marked dry season, in the Western Ghats, the Satpura and Maikal ranges, central India and parts of the Deccan, and its leaf fall during the dry months is the defining adaptation of the deciduous habit. Sal, Shorea robusta, is the corresponding dominant of the eastern and northern moist deciduous tracts, and the two rarely overlap.
• Option (b) is wrong: tropical rain forest is evergreen and dominated by dipterocarps and other tall buttressed hardwoods with no synchronised leaf fall, and teak cannot compete there.
• Option (c) is wrong: the thorn and scrub formation of the arid tracts is dominated by acacias, Prosopis and Capparis, and teak needs far more moisture.
• Option (d) is wrong: temperate forests lie in the Himalaya and carry oak, deodar, pine and fir. The governing principle is that deciduousness is a drought adaptation, so the tree defining the formation must be found where the year is divided into a wet and a dry season, which is what excludes both the always wet and the always dry options.

• Statement 3 is correct and states the Mission's objectives. The National Mission for a Green India is one of the eight missions under the National Action Plan on Climate Change, approved in 2014, and aims at increasing forest and tree cover, improving the quality of degraded forest, enhancing ecosystem services including carbon sequestration, and improving forest-based livelihoods, framed explicitly as a combined adaptation and mitigation response.
• Statement 1 is incorrect: green accounting, the incorporation of environmental depletion and degradation into national and budgetary accounts, is a separate exercise associated with natural capital accounting and the work of expert groups on green national accounts, and forms no part of the Mission.
• Statement 2 is incorrect: a second green revolution is an agricultural production objective, addressed by agricultural missions, and the Green India Mission is not an agricultural programme, the word 'green' in its title referring to vegetation cover rather than to farm output. Hence (c). The elimination route is the name itself read correctly: a candidate who fixes on 'green' as forest cover discards both the accounting and the agricultural readings at once, removing (a), (b) and (d).

REDD+ is the UNFCCC mechanism for Reducing Emissions from Deforestation and forest Degradation, with the plus denoting conservation of forest carbon stocks, sustainable management of forests and enhancement of forest carbon stocks. All three propositions follow from a well-designed scheme.

• Statement 1 is correct: forest cover retained for carbon is forest cover retained for the species it houses, and the Cancun safeguards expressly require that REDD+ actions be consistent with the conservation of natural forests and biological diversity and not be used to convert natural forest to plantation.
• Statement 2 is correct: reduced degradation and improved forest management raise the structural and functional resilience of the ecosystem to fire, drought and pest outbreak.
• Statement 3 is correct: REDD+ is built on results-based payments to the countries and communities that forgo deforestation, and community participation and benefit sharing are integral to the design, so income accrues to forest-dependent populations who are among the poorest. Hence (d).
• Options (a), (b) and (c) each exclude a genuine co-benefit. The elimination route is the framing of the stem itself: it asks what proper design and effective implementation can contribute, which is a question about potential rather than record, and on that framing no listed co-benefit can be excluded.

• Option (b) is correct. M-STrIPES stands for Monitoring System for Tigers, Intensive Protection and Ecological Status, and it is the software based patrol and monitoring protocol developed by the Wildlife Institute of India and deployed by the National Tiger Conservation Authority across tiger reserves. Forest guards on foot patrol record their tracks by GPS along with sightings, signs, carcasses and evidence of human disturbance; the data are uploaded and analysed to map patrol coverage, identify gaps in protection and generate spatial estimates of tiger and prey occupancy. It has been integral to the quadrennial All India Tiger Estimation since 2010.
• Option (a) is wrong because captive breeding is governed by the Central Zoo Authority and conservation breeding programmes, not by a patrol monitoring system.
• Option (c) is wrong: the indigenous satellite navigation system is NavIC, from the Indian Regional Navigation Satellite System.
• Option (d) is wrong: highway security has no such protocol. Elimination route: the letters STrIPES are the mnemonic, and the association with the tiger is deliberate, so the acronym itself points to the answer for a candidate who has seen the term once. Teaching point: the significance of M-STrIPES is that it converts protection from an unrecorded activity into a measurable one, so that the intensity of patrolling, and not merely its existence, can be audited against outcomes.

• Option (b) is correct. Kuno Palpur, in the Sheopur district of Madhya Pradesh, was selected as the second home for the Asiatic lion, and the Supreme Court by its order of April 2013 directed the translocation to be effected within six months. The conservation rationale is the central point and is worth teaching: the entire wild population of Panthera leo persica is confined to the Gir landscape in Saurashtra, so a single epizootic, such as the canine distemper outbreak that killed a third of the Serengeti lions in 1994, or a single catastrophic event, could extinguish the subspecies at a stroke. A geographically separate second population is insurance against that correlated risk.
• Option (a) is wrong: Corbett in Uttarakhand is a tiger landscape in Himalayan foothill terrain.
• Option (c) is wrong: Mudumalai in Tamil Nadu lies in the Nilgiri Biosphere Reserve, again tiger and elephant habitat, and in moist forest unlike the dry deciduous and scrub habitat the lion requires.
• Option (d) is wrong and is the strongest distractor, Sariska being the site of a famous translocation, but of tigers, after the reserve lost its entire population by 2004. Governing principle: match the species to the translocation, Sariska and Panna to tigers, Kuno to the Asiatic lion, and note that Kuno subsequently received African cheetahs instead, which is the ironic sequel.

• Option (d) is correct. The Earth's fossil record shows five mass extinctions, at the end of the Ordovician, in the Late Devonian, at the end of the Permian, at the end of the Triassic and at the end of the Cretaceous, each defined by the loss of a very large fraction of species in a geologically short interval. The sixth extinction is the proposition that a comparable event is under way now and that its cause is human, operating through the destruction and fragmentation of habitat, overexploitation of species, pollution, invasive species and climate change, with current extinction rates estimated at tens to hundreds of times the background rate.
• Option (d) alone names that composite set of drivers.
• Option (b) is the most instructive elimination, because it describes the cause of the fifth extinction, the end Cretaceous bolide impact, and offers it as the cause of the sixth. The whole force of the term is that this one is anthropogenic and already occurring, not extraterrestrial and prospective, so an option that returns the cause to a meteorite misses the point entirely.
• Options (a) and (c) are each real concerns, monoculture and chemical intensification in the first, genetically modified crops displacing landraces in the second, but both describe agricultural biodiversity loss, which is one narrow channel among many and cannot by itself constitute a mass extinction. Governing principle: mass extinction is a claim about species loss across all taxa and all biomes, so the correct option must be the one whose drivers are general rather than sectoral.

Hence (d).

• Statement 1 is incorrect and it is the decisive statement, since statements 2 and 3 are readily accepted and the choice reduces to (b) against (d). Heavy extraction deepens and widens the channel and lowers the riverbed, which reduces the head of fresh water opposing the sea in the lower reaches and allows the saline wedge to travel further upstream. Salinity therefore increases rather than decreases, and this is a documented outcome on rivers with heavy mining near their mouths.
• Statement 2 is correct. The sand and gravel bed is itself a natural filter through which surface water percolates to the aquifer, and stripping it removes that filtration, exposing groundwater directly to surface contaminants; the mining operation adds its own load of oil and turbidity from machinery and haulage.
• Statement 3 is correct and follows from simple hydraulics. The river surface and the surrounding water table are hydraulically connected, so lowering the bed lowers the level at which the river stands, and the adjacent water table drains down towards it. Wells near the channel then fail, which is the effect most immediately felt by riparian communities. The wider consequences worth teaching are the undermining of bridge piers and embankments by bed degradation, the loss of the hyporheic zone and its invertebrate habitat, and the destruction of spawning substrate.

Hence (b).

All three are correct and the answer is (d).

• Statement 1 is correct and follows from the physiology of the reef building corals, which depend on the symbiotic dinoflagellates in their tissues for the bulk of their energy. That symbiosis sets narrow requirements: water temperature broadly between twenty and thirty degrees Celsius, high light penetration and so shallow and clear water, normal salinity and low nutrient and sediment load. Those conditions are met between roughly thirty degrees north and thirty degrees south, and reefs are correspondingly absent from the cold upwelling coasts and from the mouths of large sediment laden rivers.
• Statement 2 is correct. Australia, Indonesia and the Philippines together account for over a third of the world's reef area, the last two lying within the Coral Triangle, which is the global centre of marine biodiversity, and the first holding the Great Barrier Reef.
• Statement 3 is correct and is the statement most often wrongly rejected. The comparison is by phylum rather than by species. Tropical rainforests hold far more species than reefs, but that diversity is concentrated within a few phyla, chiefly arthropods and chordates among animals. Reefs, being marine, host representatives of almost every animal phylum, since most animal phyla are exclusively or primarily marine, so a reef will carry sponges, cnidarians, flatworms, molluscs, annelids, arthropods, bryozoans, echinoderms, chordates and several minor phyla besides. The count usually quoted is around thirty two of the thirty four animal phyla on reefs against roughly nine in rainforests. Hence (d). Governing principle: species richness and phylum level disparity are different measures and can point in opposite directions.

• Option (a) is correct. Pakhui, also spelt Pakke, lies in the East Kameng district of Arunachal Pradesh in the foothills of the Eastern Himalaya, bounded by the Kameng river on the west and the Pakke on the east. Declared a wildlife sanctuary and later a tiger reserve, it adjoins Nameri National Park across the Assam border, and the two together form a contiguous block of lowland and foothill forest. It is best known for its hornbills, four species occurring there, and for the Hornbill Nest Adoption Programme in which Nyishi tribal youth, once hunters of the birds for their casques, are employed to protect nest trees; the reserve won the India Biodiversity Award for that work.
• Options (b), (c) and (d) are wrong, and the useful correction is to attach one protected area to each of those States so that the confusion does not recur: Manipur has Keibul Lamjao, the only floating national park, on Loktak lake, home of the sangai; Meghalaya has Nokrek and Balpakram in the Garo hills; Nagaland has Intanki and the Fakim sanctuary. The reasoning aid for Arunachal Pradesh specifically is that its protected areas are named after the rivers that bound them, Pakke, Kameng, Dibang, Namdapha and Mouling, since the State's terrain is organised by the north to south river valleys descending from the Himalaya.

Hence (a).

The Agasthyamala Biosphere Reserve lies at the southern extremity of the Western Ghats, straddling the Kerala and Tamil Nadu border around the Agasthyamala peak, and comprises Neyyar, Peppara and Shendurney Wildlife Sanctuaries on the Kerala side together with the Kalakad Mundanthurai Tiger Reserve on the Tamil Nadu side, so (a) is correct.

• Option (b) names the constituents of the Nilgiri Biosphere Reserve, the first biosphere reserve declared in India, which lies at the Nilgiri triple junction far to the north, so it is wrong.
• Option (c) mixes Andhra Pradesh sanctuaries, Kaundinya in Chittoor and Gundla Brahmeswaram in the Nallamalas and Papikonda in the Eastern Ghats, with Mukurthi in the Nilgiris, a combination that belongs to no single reserve and is wrong.
• Option (d) names Telangana and Andhra Pradesh protected areas of the Eastern Ghats and the Nallamala hills, well outside the Western Ghats, so it is wrong. The elimination route is geographical rather than encyclopaedic. A candidate who knows only that Agasthyamala lies at the southern tip of the Western Ghats can discard (c) and (d) as Eastern Ghats clusters and discard (b) as the Nilgiri set, reaching the answer without knowing the four constituent units by name.

On the figures current when the paper was set, forest cover as a percentage of geographical area stood at roughly sixteen and a half per cent for Maharashtra, about twenty five per cent for Madhya Pradesh, about thirty three per cent for Odisha and about forty one per cent for Chhattisgarh. The correct ascending order is therefore Maharashtra, Madhya Pradesh, Odisha, Chhattisgarh, that is 3-2-4-1, so (c) is correct.

• Options (a) and (b) both begin with Madhya Pradesh, which is wrong because Madhya Pradesh leads on absolute forest area but not on proportion, its very large geographical area diluting the percentage; this confusion between area and share is precisely the trap the question is built on.
• Option (d) has the first two States right but reverses the last two, placing Chhattisgarh below Odisha, whereas Chhattisgarh has the highest proportion of the four. The elimination route needs only two facts. Recognising that Maharashtra, with its large Deccan plateau of dry cultivated and degraded land, has the lowest share removes (a) and (b), and recognising that Chhattisgarh, dominated by the Bastar and Surguja forest belts, has the highest share then decides between (c) and (d).

The hard ground barasingha, Rucervus duvaucelii branderi, is the central Indian subspecies whose hooves are adapted to firm rather than marshy terrain and which grazes almost exclusively on grasses. Kanha is its last natural stronghold and the site of the recovery that brought it back from a few dozen animals, which is why it is the state animal of Madhya Pradesh and the park mascot, giving (a).

• Option (b) is wrong because Manas holds the eastern swamp deer, a distinct subspecies of the wet terai and floodplain.
• Option (c) is wrong because Mudumalai in the Nilgiris is known for elephant, gaur and tiger and lies outside the swamp deer range entirely.
• Option (d) is wrong because Tal Chhapar in the Rajasthan desert is a blackbuck sanctuary on saline flat grassland.

• Statement 1 is correct. The Desert National Park extends across the Jaisalmer and Barmer districts of Rajasthan and is among the largest protected areas in India, covering roughly three thousand one hundred and sixty square kilometres of sand dune, sewan grassland and salt flat.
• Statement 3 is correct and is the reason the park matters, since it holds the largest surviving population of the great Indian bustard, a critically endangered species whose principal threat is now collision with overhead power lines crossing its habitat.
• Statement 2 is incorrect and is the discriminating statement. A substantial resident population lives inside the park in a number of villages, grazing livestock on the same grassland, and this coexistence is precisely the management problem that has dogged the park since notification. The answer is 1 and 3, giving (c).
• Options (a), (b) and (d) all accept the claim of no habitation, which no large Indian protected area in an inhabited desert could satisfy.

Critical tiger habitat is the core area of a tiger reserve, notified under the Wild Life Protection Act on the advice of an expert committee and required to be kept inviolate. Nagarjunsagar Srisailam, straddling Andhra Pradesh and Telangana in the Nallamala hills along the Krishna, is the largest tiger reserve in India and has the largest notified core, of the order of two and a half thousand square kilometres, giving (c).

• Option (a) is wrong because Corbett, though the oldest and among the densest in tiger numbers, has a core of about eight hundred square kilometres.
• Option (b) is wrong because Ranthambore's core is of the order of eleven hundred square kilometres.
• Option (d) is wrong because the Sunderbans core, at about seventeen hundred square kilometres, is large but still smaller than Nagarjunsagar Srisailam. The trap is that the three wrong options are the more famous reserves, while the correct answer is the largest but least celebrated.

Three clues in the passage converge on one biome. Rapid litter decomposition indicates continuously high temperature and humidity driving intense microbial and fungal activity, which strips nutrients into biomass and leaves the soil poor and bare. Competition for light through climbing lianas and epiphytes indicates a dense multi layered closed canopy. Both are diagnostic of the tropical rain forest, so option (d) is correct.

• Option (a) fails because coniferous forests accumulate thick, slowly decomposing acidic needle litter forming podzols.
• Option (b) fails because dry deciduous forests shed leaves seasonally and have open canopies with abundant ground light.
• Option (c) fails because mangroves are defined by tidal inundation, saline substrate and pneumatophores, none of which the passage mentions. Hence (d). The nutrient paradox, luxuriant vegetation on impoverished soil, is the concept being tested.

• Statement 1 is not correct, and the error is a single substituted institution: the Tree Cities of the World programme is run jointly by the Food and Agriculture Organization and the Arbor Day Foundation, not by the United Nations Capital Development Fund, whose mandate is development finance in least developed countries.
• Statement 2 is correct: recognition is conferred annually and requires a city to meet five standards, namely establishing responsibility, setting rules, maintaining an inventory of tree resources, allocating resources, and celebrating achievements, so it does follow from a demonstrated commitment to grow and maintain urban forests. Since the first is wrong and the second right, the answer is (d). The item illustrates a design UPSC has used increasingly since 2021, the Statement 1 and Statement 2 format, in which the two statements must be assessed independently before any question of explanation arises.

• Pair 1 is incorrectly matched. Hokera, or Hokersar, is a Ramsar site in the Kashmir valley of Jammu and Kashmir, lying north west of Srinagar and fed by the Doodhganga, and it is a well known wintering ground for migratory waterfowl on the Central Asian Flyway. It is not in Punjab.
• Pair 2 is correctly matched. The Renuka wetland lies in Sirmaur district of Himachal Pradesh and is the state's largest natural lake, designated under the Ramsar Convention.
• Pair 3 is correctly matched. Rudrasagar, also called Twijilikma, is in Tripura and is a Ramsar site, best known for the Neermahal palace standing in it.
• Pair 4 is incorrectly matched. Sasthamkotta is in Kollam district of Kerala and is the largest freshwater lake in that state, supplying drinking water to Kollam town. It is not in Tamil Nadu. Exactly two pairs are correct, so (b) is the answer.
• Option (a) understates and options (c) and (d) overstate the count, each requiring at least one of the two clear misplacements to be accepted.

The analogy has to be read for what the organ does. A kidney filters the blood and removes dissolved wastes and excess solutes from circulation. The wetland function that corresponds is the removal of dissolved contaminants from water, and option (d) states it: aquatic macrophytes take up heavy metals and strip excess nitrogen and phosphorus, which is the basis of constructed wetlands for effluent treatment and of the natural purification that wetlands perform for the catchments they sit in.

• Option (a) describes hydrological pathways, which relate to water storage and recharge rather than to purification.
• Option (b) describes primary productivity and the food web the wetland supports, a nutritive rather than an excretory function.
• Option (c) is the strongest distractor because sediment trapping is genuinely a filtering action, but it is a physical settling of suspended particles that better answers a description of the wetland as a sieve; the kidney metaphor points to the removal of dissolved substances, which is what (d) alone supplies.

Hence (d).

Biorock, also called mineral accretion technology, restores coral reefs by passing a low voltage direct current through a submerged steel frame. The current drives electrolysis at the cathode, raising the local pH and precipitating calcium carbonate from the dissolved ions in seawater, so that limestone accretes onto the frame and provides a substrate on which coral fragments transplanted to it grow faster and survive stress better than they otherwise would.

• Option (a) states this and is correct.
• Option (b) describes agro residue based construction materials, an unrelated line of work in building science.
• Option (c) describes hydrocarbon prospecting, which relies on seismic surveying and geological assessment of shale formations, not on electrolytic accretion.
• Option (d) describes a wildlife management practice of supplying mineral supplements to herbivores, which has nothing to do with the marine environment.

Hence (a).

The method is named for the Japanese botanist Akira Miyawaki, who developed a technique for establishing dense native woodland on small plots. Native species of several canopy layers are planted very close together in deeply prepared and amended soil, so that competition for light drives rapid vertical growth and the stand closes canopy and becomes self sustaining within a few years, far faster than conventional plantation. Its best known application is the urban pocket forest, which is why option (c) is correct.

• Option (a) is wrong because the method is a forest restoration technique concerned with native ecosystems, not a commercial farming system for drylands.
• Option (b) is wrong because the method depends specifically on locally native species selected from the potential natural vegetation, and involves no genetic modification.
• Option (d) is wrong because it describes offshore and coastal wind power, an unrelated field.

Hence (c).

Community Reserves were introduced by the 2002 amendment to the Wild Life Protection Act as Sections 36C and 36D, covering private or community land where a community or an individual volunteers to conserve wildlife.

• Statement 1 is clearly incorrect. The governing authority is the Community Reserve Management Committee constituted under Section 36D, comprising village representatives and the concerned Forest or Wildlife Warden as member secretary, not the Chief Wildlife Warden.
• Statement 2 follows from Section 36C(2), which applies the sanctuary provisions on hunting mutatis mutandis, so hunting is prohibited.
• Statement 3 reflects the fact that the reserve is declared over land whose existing use continues, and collection of non timber forest produce is not extinguished by the declaration.
• Statement 4 follows from Section 36D(2), which bars change in land use pattern except by resolution of the Management Committee with State approval, thereby preserving existing agricultural practice. On that reading three statements are correct and the answer would be (c). The official key at (b) accepts only two.

The Cuvette Centrale peatland complex in the central Congo Basin, straddling the Republic of the Congo and the Democratic Republic of the Congo, is the world's largest tropical peatland at roughly 145000 square kilometres, storing about 30 billion tonnes of carbon, comparable to three years of global fossil fuel emissions. Its exposure to oil and gas licensing and drainage is the reason it is described as a climate risk.

• Option (a) is wrong because the Amazon Basin, although the largest tropical forest carbon store, holds its carbon chiefly in above ground biomass rather than in peat, and its peatlands such as the Pastaza Maranon complex are far smaller.
• Option (c) is wrong because the Kikori Basin in Papua New Guinea has peatlands of only regional significance.
• Option (d) is wrong because the Rio de la Plata Basin is dominated by grassland, wetland and agricultural landscapes rather than tropical peat.

Only statement 3 states a genuine rationale, so (d) is correct. Mangroves dissipate wave and surge energy through their dense aerial root systems, which is the bio-shield function demonstrated along the Odisha and Sundarbans coasts, and they supply fuelwood, fodder, honey and nursery grounds for fisheries, which is the livelihood function. Both are reasons to protect the ecosystem.

• Statement 1 is wrong twice over, because mangroves do not store freshwater and, more importantly, the sentence ends by proposing their conversion to paddy fields, which is a driver of mangrove loss rather than a reason to protect them.
• Statement 2 is wrong on the physiology and on the conclusion, since mangrove roots are the roots of halophytes and are salt tolerant rather than salt sensitive, excluding or excreting salt rather than filtering seawater into fresh, and conversion to aquaculture ponds is historically the single largest cause of mangrove destruction in South and Southeast Asia.
• Options (a), (b) and (c) each admit at least one statement that argues for destroying the ecosystem in a question about protecting it.

• Statement 1 is correct, since Madhav in Shivpuri district was notified in 2025 as India's fifty eighth tiger reserve and the ninth in Madhya Pradesh.
• Statement 2 is correct, since Sakhya Sagar, an artificial lake created on the Manier river in the early twentieth century, lies within the park and was designated a Ramsar site in 2022 along with several other Indian wetlands.
• Statement 3 is incorrect and is the eliminator, because Madhav National Park lies wholly within Shivpuri district of Madhya Pradesh and shares no area with Rajasthan, although Shivpuri is not far from the interstate boundary, which is what makes the distractor plausible. Hence 1 and 2 and (b) is correct. (a) drops the Ramsar link, and (c) and (d) accept the false interstate claim.