Haemophilia is more commonly seen in human males than in human females because
This disease is due to an $X$-linked dominant mutation
A grater proportion of girls die in infancy
This disease is due to an $X$-linked recessive mutation
This disease is due to a $Y$-linked recessive mutation
A boy is colour blind, in his two sisters one is colour blind and one is carrier $(normal)$. Then who is colour blind in his family
If a colour blind lady marries a normal man, their children will be
Colour blindness results from
If a man who is colour blind marries a women, who is pure normal for colour vision, the chances of their sons have colour blindness is