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Topic Sex determination
Asked 2 times across 2 UPSC exams over 39 years (1981–2020), peaking in 1981.
Key insights
- Most tested in CSE — 1 of 2 PYQs
- Most asked in 1981
- Recurs across 2 years (1981–2020)
How it travelled across exams
First appearance in each exam — the same idea, reframed.
CSE 1981 → CDS 2020
How the concept evolved
Long-running — most appearances (1 of 2) predate 2016, and it still returns.
Related concepts
Ideas UPSC tests alongside this one — keep exploring.
Sample questions
You've seen the pattern — here are a few of the actual PYQs.
CDS2020
In human beings, the chromosomes that determine birth of a normal female child are
- A one X chromosome from mother and one X chromosome from father ✓
- B one X chromosome from mother and one Y chromosome from father
- C two X chromosomes from mother and one X chromosome from father
- D one X chromosome from father and one Y chromosome from mother
✓ Correct answer: (A)
Science & Technology › Biology & Health
CSE1981
The sex of the offspring is determined, when
- A The conception takes place ✓
- B The sperm fertilises the ovum
- C The embryo is partially developed
- D The end of gestation period is near
✓ Correct answer: (A)
Science & Technology › Biology & Health
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