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

Gene for colourblindness is located on

Sickle-cell anaemia happens due to …$A$… mutation in which …$B$… of haemoglobin is affected.

Fill the correct option for $A$ and $B$

Give scientific reasons : The Mendelian experiments cannot be carried out in human beings.