Question

Assertion (A) : The sex of a child in human beings will be determined by the type of chromosome he/she inherits from the father.
Reason (R) : A child who inherits ‘X’ chromosome from his father would be a girl (XX), while a child who inherits a ‘Y’ chromosome from the father would be a boy (XY).

• A. Both (A) and (R) are true, but (R) is not the correct explanation of the assertion (A).
• B. (A) is false, but (R) is true.
• C. Both (A) and (R) are true and (R) is the correct explanation of the assertion (A).
• D. (A) is true, but (R) is, false.

Answer 1

The correct option is C Both (A) and (R) are true and (R) is the correct explanation of the assertion (A).

In humans, the father has both XY as sex chromosomes while the mother has only XX as sex chromosomes. Hence, during the fusion of gametes, the mother can only provide the X chromosome while the father can provide either the X or Y chromosome.

So, if the child receives X chromosomes from the father then X of the father will pair with X of the mother to form the female, while if the father's gamete gives a Y chromosome, then it's pairing with X of the mother will result into XY which will form the male child.