$A$ normal woman,whose father was color-blind,marries a normal man. What will be the status of their sons?

Phenylketonuria is an inborn error of metabolism that is inherited as:

$A$ husband and wife both have normal vision,although both of their fathers were colorblind. What is the probability that their daughter will be colorblind (in $\%$)?

Given below is a pedigree chart of a family with five children. It shows the inheritance of attached earlobes as opposed to the free ones. The squares represent the male individuals and circles the female individuals. Which one of the following conclusions drawn is correct?

$A$ colour-blind man marries the daughter of a colour-blind person. Then in their progeny:

Which one is a sex-linked disease?