If an albino man marries a normal woman and $50$ offspring are albino and $50$ are normal,the woman is:

$A$ woman with normal vision marries a man with normal vision and gives birth to a color-blind son. Her husband dies,and she remarries a color-blind man. What is the probability of color blindness in her children from the second marriage?

One of the genes present exclusively on the $X$-chromosome in humans is concerned with

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

Thalassemia and sickle cell anaemia are caused due to a problem in globin molecule synthesis. Select the correct statement.

Sickle-cell anaemia happens due to $A$ mutation in which $B$ of haemoglobin is affected. Fill the correct option for $A$ and $B$.