Alkaptonuria is caused due to

Assertion : Persons suffering from haemophilia fail to produce blood clotting factor $VIII$.
Reason : Prothrombin producing platelets in such persons are found in very low concentration.

Give differences: Haemophilia and Sickle-cell Anaemia.

$A$ man whose father was colorblind marries a woman who has a colorblind mother and a normal father. What is the percentage probability of their male children being colorblind (in $\%$)?

Who among the following is associated with biochemical genetics?

Mr. Stevan is suffering from haemophilia and cystic fibrosis. His father is heterozygous for cystic fibrosis. The probability of Stevan's sperm having recessive $X$-linked as well as autosomal allele is