Fact 1: Sight is the ability to sense light, and the eye is the organ that senses light.

Fact 2: Inside the eye, at the back, is the retina.

Given the two facts above, answer the question "what involves the retina?" with the following options: 
- gravity
 - disease
 - h2o
 - reacts
 - CO 2
 - digestion
 - painful
 - sight


 

        sight 