UPSC Prelims 2021— Question 36

Mitochondrial replacement therapy is designed to prevent transmission of pathogenic mitochondrial DNA by replacing defective maternal mitochondria, and the intervention must be undertaken as part of the reproductive process rather than after a child has inherited the disease. Mitochondrial DNA is inherited predominantly from the mother because sperm mitochondria are generally not transmitted to the embryo. Thus the accepted answer is that both statements are correct. The final answer-key position for Set C identifies option C as the correct option. Option A — 1 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 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 — Both 1 and 2 — is correct because it is the alternative that matches the constitutional, historical, geographical, scientific or economic principle established above. Option D — Neither 1 nor 2 — 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.