The gene for haemophilia is located on the $X$ chromosome. Hence,it is normally impossible for a:

In an individual with phenylketonuria,there is an enzyme deficiency. This enzyme converts phenylalanine into ........ .

If a father shows a normal genotype for hemophilia,what will be the outcome for his children?

$A$ man and a woman,who do not show any apparent signs of a certain inherited disease,have seven children ($2$ daughters and $5$ sons). Three of the sons suffer from the given disease but none of the daughters are affected. Which of the following modes of inheritance do you suggest for this disease?

Select the correct options for the given statements:
Statements:
$X$: Formation of Haemoglobin is controlled by two closely linked genes $HBA1$ and $HBA2$ on chromosome $16$ of each parent.
$Y$: $\beta$-Thalassemia is controlled by a single gene $HBB$ on chromosome $21$ of each parent.

Identify the incorrect statement.