The IRIS is the colored sections, which vary depending on the races. Function of IRIS is to help control the size of the hole in the IRIS, by contraction or expansion of the eye muscles.
The iris is the colored part, which varies depending on the race. The function of the iris is to control the size of the pupil. By contraction or expansion of the diaphragm muscle.
Iris is the color which is different depending on the race. Function of iris is to help to control the size of the pupils. By the contraction or expansion of the muscle of iris.