Question

multiple - choice question
what causes color blindness?
something is not functioning with one type of cone
something is wrong with their retina
rewatch

Explanation:

Color blindness is often caused when one type of cone - cells in the eye, which are responsible for color - vision, is not functioning properly. While the retina is involved, the more specific issue is with the cones.

Answer:

something is not functioning with one type of cone