Pedigree analysis is $NOT$ useful for which of the following purposes?

$A$ colorblind man marries a woman who is the daughter of a colorblind father. What will be the status of their offspring regarding colorblindness?

Haemophilia is a condition where there is . . . . . .

Given below are two statements:
Statement $I$: Sickle cell anaemia and Haemophilia are autosomal dominant traits.
Statement $II$: Sickle cell anaemia and Haemophilia are disorders of the blood.
In the light of the above statements,choose the correct answer from the options given below:

Which of the following disorders is characterized by mental retardation?

Sickle-cell anaemia is