Question

A color blind girl is rare because she will be born only when
(a)Her mother and maternal grandfather were color blind
(b)Her father and maternal grandfather were color blind
(c)Her mother is color blind and father has normal vision
(d)Parents have normal vision but grandparents were color blind

Answer 1

Males are more likely to be color blind than females in humans, since the genes on the X chromosome are responsible for the most common forms of color blindness. Males only have one X chromosome and, thus, if they have the recessive gene, they always show the genetic condition.

Complete answer:
A color-blind girl is unusual because only when her father and maternal grandfather are color-blind, will she be born there. The mother's genotype was to be either ${ X }^{ c }{ X }^{ c }$ or ${ X }^{ c }{ X }$, and the father's genotype was to be ${ X }^{ c }Y$ in order to make the daughter color blind.
A hereditary issue in the development of one or more of the three sets of cone cells of the eyes, which sense color, is the most common cause of color blindness.
Females have two X chromosomes, so the other usually compensates for a mutation in one. For color blindness, non-color-blind females may carry genes and pass them on to their children.
Physical or chemical damage to the retina, the optic nerve, or parts of the brain may also result in color blindness. Usually, diagnosis is with the Ishihara color test and genetic testing.

Additional Information: Approximately 1 in 12 men (8 percent) and 1 in 200 women in the world are affected by color blindness (color vision deficiency or CVD). This means that there are about 3 million color-blind people in Britain (about 4.5 percent of the entire population), most of whom are male.
So, the correct answer is, ‘Her father and maternal grandfather were color-blind’.

Note: When you are unable to see colors in a typical way, color blindness happens. It is known as a color deficiency as well. Color blindness also occurs when someone is unable to differentiate between certain colors. Typically this occurs between greens and reds, and also between blues.