The disease 'Haemophilia' is caused due to the lack of:

The $ . . . . . . $ is regarded as an inborn metabolic disorder.

Quantitative defect of hemoglobin $- P$
Qualitative defect of hemoglobin $- Q$
Select the correct option for $P$ and $Q$.
$\quad \quad P\quad \quad \quad Q$

If a color-blind woman marries a normal man,their offspring will be:

$A$ man and a woman who do not show any apparent symptoms of certain genetic diseases 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 type of inheritance pattern do you suggest for this disease?

Describe Mendelian disorders.