Fact 1: When light enters the eye through the pupil , that light falls on the retina.

Fact 2: Humans use both eyes to see a single image.

Given the two facts above, answer the question "What do humans use to see an image?" with the following options: 
- keratin
 - light
 - heat
 - fibers
 - calcite
 - mussels
 - photons
 - Neuron.


 

  light       