UPSC Prelims 2021— Question 80

Species of cnidarians, fungi and protozoa can participate in symbiotic associations. Coral cnidarians have mutualistic relationships with photosynthetic algae; fungi form mycorrhizal and lichen associations; protozoa can live symbiotically in the guts of organisms such as termites. Therefore all three categories are accepted. The final answer-key position for Set C identifies option D as the correct option. Option A — 1 and 2 only — is not correct because it does not satisfy the specific condition tested in the question; it represents an alternative that is contradicted, incomplete, or less precise than the accepted answer. Option B — 2 and 3 only — is not correct because it does not satisfy the specific condition tested in the question; it represents an alternative that is contradicted, incomplete, or less precise than the accepted answer. Option C — 1 and 3 only — is not correct because it does not satisfy the specific condition tested in the question; it represents an alternative that is contradicted, incomplete, or less precise than the accepted answer. Option D — 1, 2 and 3 — is correct because it is the alternative that matches the constitutional, historical, geographical, scientific or economic principle established above. For PYQ interpretation, the distinction between the correct alternative and merely related facts is important. UPSC often places plausible distractors beside the precise statement that matches the underlying rule, chronology, definition or empirical relationship. The answer should therefore be read against the exact wording of the question rather than against a broadly related fact.