UPSC Prelims 2023— Question 70

This question tests Microsatellite DNA under Biotechnology & Genetics. The central point is Microsatellites are genetic markers used to study variation and evolutionary relationships. Option A: Studying the evolutionary relationships among various species of fauna. This is the keyed answer because it matches the governing fact or concept: Microsatellites are genetic markers used to study variation and evolutionary relationships. Option B: Stimulating 'stem cells' to transform into diverse functional tissues. This distractor is not the keyed answer because it conflicts with the specific factual relationship, chronology, institutional role, geographic association or conceptual distinction tested in the question. Option C: Promoting clonal propagation of horticultural plants. This distractor is not the keyed answer because it conflicts with the specific factual relationship, chronology, institutional role, geographic association or conceptual distinction tested in the question. Option D: Assessing the efficacy of drugs by conducting series ~f drug trials in a population. This distractor is not the keyed answer because it conflicts with the specific factual relationship, chronology, institutional role, geographic association or conceptual distinction tested in the question. The question should be approached by checking each statement independently rather than accepting a familiar phrase at face value. This is particularly important in UPSC questions where a single incorrect institutional attribution, location, chronology, absolute word or causal link can invalidate an otherwise plausible option. The broader revision takeaway is to connect the keyed answer with the underlying concept rather than memorizing only the letter. The options also illustrate how UPSC constructs distractors by mixing correct facts with one altered detail. In revision, candidates should therefore retain both the positive fact and the nearest contrasting fact so that the same concept can be recognized when the framing changes in another year.