Question

practice it
what is the structure of the eye that plays a key role in focusing light onto the retina?
lens
iris
cornea
pupil
optic nerve

Explanation:

The lens of the eye changes shape to focus light onto the retina. The iris controls the amount of light entering, the cornea is the front - most clear part that also refracts light but the key focusing is done by the lens. The pupil is the opening in the iris and the optic nerve transmits visual information from the retina to the brain.

Answer:

A. Lens