question_answer

If a colour-blind man marries a woman who is homozygous for normal colour vision, the probability of their son being colour-blind is

A)  0

B)  0.5

C)  0.75

D)  1

Correct Answer: A

Solution :

 Colour blindness is X-linked recessive disease and shows criss-cross inheritance. 100% - carrier daughters (Phenotypically normal) 100%-Normal son