An object is moved farther away from a normal eye. To keep forming a sharp image on the retina, the eye's lens must undergo which change, and why? image must continue to form at the fixed image distance (on the retina)
The lens must thicken further, since image distance needs to increase
The lens must become thinner (ciliary muscles relax), increasing focal length, since the
No change is needed at all
The pupil must change into a lens shape