Question

Which light-sensitive cells are present in abundance and give their function

Answer 1

Light-sensitive cells are present in the retina in abundance...to be more specific the fovea centralis is the place of highest concentration of light-sensitive cells

theses cells are of two types- rods and cones...

Rod cells or Rods - rods are responsible for night vision. 

Cone cells or Cones - cones are responsible for coloured images during bright light.

Answer 2

light-sensitive cells are present in abundance is cones and rod cells.

The rods respond to intensity or brightness of light, while the cones respond to colours. The cones make it possible to distinguish between different colours. Colour blindness is a defect where a person is unable to distinguish between different colours. This is because he/she has defective cone cells.