Alkaptonuria is a disease where the urine is:

$A$ son of a colourblind father and a normal homozygous mother marries a daughter of a normal father and a heterozygous (carrier) mother. What will be the phenotype of their children?

The 'Thala test' is performed for the confirmation of:

$A$ normal-visioned man whose father was colour-blind,marries a woman whose father was also colour-blind. They have their first child as a daughter. What are the chances that this child would be colour-blind?

What is the cause of haemophilia?

In a cross between a male and female, both heterozygous for sickle cell anaemia gene, what percentage of the progeny will be diseased? (In $ \%$ )