UPSC CIVIL SERVICES PRELIMINARY EXAMINATION

UPSC Prelims 2021— Question 78

2021General Studies Paper-IEnvironment & EcologyEcologyFood Webmoderate
Q78

Question

Which of the following are detritivores? 1. Earthworms 2. Jellyfish 3. Millipedes 4. Seahorses 5. Woodlice. Select the correct answer using the code given below.

Options

A
1, 2 and 4 only
B
2, 3, 4 and 5 only
C
1, 3 and 5 only✓ Correct Answer
D
1, 2, 3, 4 and 5
AnswerOption C

Explanation

Earthworms, millipedes and woodlice are detritivores that feed on dead organic matter and help fragment litter, facilitating decomposition. Jellyfish and seahorses are consumers but not detritivores. Thus statements 1, 3 and 5 are correct. The final answer-key position for Set C identifies option C as the correct option. Option A — 1, 2 and 4 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, 3, 4 and 5 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, 3 and 5 only — is correct because it is the alternative that matches the constitutional, historical, geographical, scientific or economic principle established above. Option D — 1, 2, 3, 4 and 5 — 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. 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.

Question Classification

SubjectEnvironment & Ecology
TopicEcology
SubtopicFood Web
Question TypeSingle-answer conceptual/factual
Difficultymoderate
VerificationVerified