Environment & Ecology MCQs for UPSC Prelims

Correct answer: A - 1, 2 and 3 only

The lion-tailed macaque is an endemic primate of the Western Ghats and is found only in the rainforest pockets of the southern Western Ghats, which fall in Tamil Nadu, Kerala and Karnataka, so option (a) is correct. Andhra Pradesh lies on the eastern side of the peninsula and has no Western Ghats rainforest habitat, which rules out statement 4 and therefore options (c) and (d). Option (b) is too restrictive because the species is not confined to Kerala alone but ranges across all three western coastal states named.

Correct answer: C - 1 and 3 only

The Desert National Park in Rajasthan is spread across the Jaisalmer and Barmer districts, so statement 1 is correct, and it is one of the last strongholds of the critically endangered Great Indian Bustard, so statement 3 is correct. Statement 2 is wrong because several villages and human settlements exist within and around the park, making it an inhabited protected area unlike many wildlife reserves. Hence only statements 1 and 3 are correct.

Correct answer: B - 1, 2 and 4 only

Sustainable Sugarcane Initiative (SSI) is a method that raises seedlings in a nursery and transplants young single-budded setts, which sharply cuts the quantity of seed cane needed, so statement 1 is correct. Wider spacing makes drip irrigation and fertigation highly effective, so statement 2 is correct, and the gaps between widely spaced plants leave room for intercropping, so statement 4 is correct. Statement 3 is wrong because SSI promotes balanced and reduced use of inputs and integrated nutrient management, not the total elimination of chemical or inorganic fertilizers. Hence 1, 2 and 4 only.

Correct answer: D - 1, 2 and 3

Cnidarians such as corals host symbiotic zooxanthellae algae, so statement 1 holds. Fungi form symbioses such as lichens with algae and mycorrhizae with plant roots, so statement 2 holds. Protozoa also form symbiotic relationships, for example the cellulose-digesting protozoa living in the guts of termites and ruminants, so statement 3 holds. Since all three groups have symbiotic species, the answer is 1, 2 and 3.

Correct answer: C - 2, 4 and 5

Conservation agriculture rests on three core principles: minimum mechanical soil disturbance, permanent soil cover with residues, and diversified crop rotations, which correspond to statements 2, 4 and 5, so option (c) is correct. Statement 1 about avoiding monoculture is broadly desirable but conservation agriculture is defined by crop rotation and diversification rather than framed as 'avoiding monoculture', and the practice does not specifically prohibit monoculture as a defining rule. Statement 3 is wrong because conservation agriculture does not require avoiding plantation crops; it is concerned with how soil and residues are managed, not with banning particular crop categories. Hence 2, 4 and 5 is the answer.

Correct answer: C - 1 and 3 only

Practices 1 and 3 conserve soil moisture: reduced or zero tillage avoids exposing moist soil to evaporation, and leaving crop residue mulches the surface, cutting evaporative loss and runoff. Gypsum (practice 2) is mainly a soil amendment used to reclaim sodic/alkaline soils and improve structure rather than a water-conservation step, so the official key excludes it. The answer is therefore 1 and 3 only. This was a disputed question because some sources argue gypsum improves infiltration, but the official UPSC key marks option C.