Consider the following statements:
Assertion (A): In humans, female sex is determined by XX-chromosomes.
Reason (R): Male sex is determined by YY-chromosomes.

Options

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

Answer

C

Explanation

Humans are diploid with 23 pairs of chromosomes. Of this, 22 pairs are somatic and the one pair is sex chromosomes. This particular pair exists as XX in human females and XY in males. The presence of two X chromosomes contributes to the female phenotype while presence of only one Y chromosome is responsible for the human to be male. Females produce only X-type haploid gametes and males produce two types (X and Y) of haploid gametes. Fusion of either X or Y of male gamete with the female gamete determines the sex of the offspring