How do we see colours ?

Explanation

The retina of our eye contains numerous cells, which are light sensitive. These cells are of two types : rod shaped cells respond to brightness//intensity of light and cone shaped cells respond to colour of light. When light falls on the retina, these cells get activated. They send electrical signals to the brain through the optic nerve. The brain processes this information and we see objects as they are. Thus colours are seen due to activation of cone shaped cells.