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JAMB Biology 2010 Question 48

Question 48

Chromosomes, DNA and Sex Linkage

At what stage in the life history of a mammal is the sex of an individual set?

  1. A.At puberty.
  2. B.At birth.
  3. C.At conception.
  4. D.At adolescence.
Show the answer and explanation

Answer: C (At conception.)

Explanation

The egg always carries an X chromosome. Whether the sperm that fertilises it carries X or Y decides the sex at the moment of conception.