Question

in human eye the focussing is done by
1) to and fro movement of Retina
2)to and fro movement of eye lens
3)change in convexity of lens
4)change in Refractive Index of a fluid

Answer 1

change in convexity of lens...
hope it will help you if it is right then mark as

Answer 2

according to me 2)to and fro movement of eye lens.....