A) Pupil control the amount of light entering the eye.The pupil changes size to adjust for amount of light available.
b) Retina is the nerve layer lining back of the eye. The retina senses light and convert it into neural signals that are sent to the brain.
c) Cornea transplantation involves replacing the cornea. In this process only cornea is replaced..Eye donation should be encouraged because it's just like a priceless gift which one person give to other and also this is how even after death he or she is alive..