Official Answer Key & Detailed Solution
Ready to check the official UPSC Answer Key?
Click any option above to test yourself under exam conditions, or reveal the explanation directly.
Correct Answer: Option (D) — A is false but R is true
Concept & Option Breakdown
Standard Reference Verified• Assertion (A) is false: Human females are homogametic (XX) and produce only X-bearing ova, whereas males are heterogametic (XY) and produce 50% X-bearing and 50% Y-bearing sperm. Fertilization by an X or Y sperm determines whether the offspring is female (XX) or male (XY). Thus, the father's gamete determines the sex. • Reason (R) is true: Human females possess two homomorphic sex chromosomes (XX).
Human sex determination is XY (male heterogamety). The male determines the sex, making Assertion (A) false.
Practice Full-Length & Sectional Prelims Mocks on this Interface
50 simulated tests in the APT Prelims Test Series (₹1,493) or 1-on-1 Mentorship with Avinash Sir.