Question

A person has normal vision but he cannot distinguish between red green colors

Answer 1

Person is colour blind
and color blindness is X-linked recessive disorder.

The exact physical causes of colour blindness are still being researched but it is believed that colour blindness is usually caused by faulty cones but sometimes by a fault in the pathway from the cone to the brain.

Answer 2

Due to small number of

cone cells which are responsible for distinguishing colours