Question

why iris is colourful?????

Answer 1

$\huge\mathfark{ANSWER}$
The function of the iris is to limit the amount of light that passes through the lens to the retina. To make the iris opaque, it is coated with the pigment melanin, in varying degrees for each of us. Melanin makes the eyes dark brown and 10,000 years ago, everyone's eyes were this colour.

Answer 2

To make the iris opaque, it is coated with the pigment melanin, in varying degrees for each of us. Melanin makes the eyes dark brown and 10,000 years ago, everyone's eyes were this colour.