In pedigree analysis, symbol given for sex unspecified is

A colourblind daughter is born when

What are all the chances of colour blind daughter and sons being born in a marriage of normal man marrying a normal woman, whose father was colour blind

Sickle-cell anaemia happens due to ...$A$... mutation in which ...$B$... of haemoglobin is affected.

Fill the correct option for $A$ and $B$

Genes for colour blindness is carried by

$I.$ Abnormal development

$II.$ Father

$III.$ Mother

$IV.$ Autosomes

Why is the frequency of red-green colour blindness is many times higher in males than that in the females ?