Blackening of urine,when exposed to air,is a metabolic disorder in human beings. This is due to:

Phenylketonuria is an inborn error of metabolism that is inherited as:

In the $\beta$-globin chain of haemoglobin of an individual,if the sixth amino acid,Glutamic acid (Glu),is replaced by Valine (Val),then the individual will be suffering from:

Absence of teeth,bifid tongue and mental retardness are observed in . . . . . . .

Hemophilia is more common in human males than in females because it is a:

$A$ 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?