Mental retardation in children suffering from galactosemia can be avoided by

Albinism in humans is controlled by a recessive gene. If a couple has children and $50\%$ of them exhibit albinism,what does this indicate about the parents' genotypes?

Sickle cell anemia and Huntington's chorea are both ..........

$A$ man whose father was colour blind marries a woman who had a colour blind mother and normal father. What percentage of male children of this couple will be colour blind (in $\%$)?

Assertion: Phenylketonuria is an autosomal recessive hereditary disease caused by the body's failure to oxidize the amino acid $phenylalanine$ to $tyrosine$ due to a defective enzyme.
Reason: It results in the accumulation of $phenylpyruvic$ acid and its derivatives in the urine.

Given below is a pedigree chart showing the inheritance of a certain trait in humans. Select the correct option for the given chart.