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

Sickle -cell anaemia has not been eliminated from the African population because it

Colour blindness is a disease usually affecting man but the factor for it is transmitted to the children always by woman. This is because particular factor is located on

Pick out the correct statements.

$I.$ Haemophilia is a sex-linked recessive disease

$II.$ Down's syndrome is due to aneuploidy

$III.$ Phenylketonuria is an autosomal dominant gene disorder

$IV.$ Phenylketonuria is an autosomal recessive gene disorder

$V.$ Sickle cell anaemia is an $X$-linked recessive gene disorder

A sex linked recessive gene $C$ produces red green colour blindness in humans. A normal woman whose father was colourblind marries a colourblind man. Of all the girls born to these parents what percentage is expected to be colourblind

A man known to be victim of haemophilia marries a normal woman whose father was known to be a bleeder. Then it is expected that