Binocular vision refers to the ability to:

A) focus on objects at a distance.
B) bring an object in and out of focus.
C) focus on an object with both eyes.
D) visually distinguish between similar colors.

Binocular vision refers to the ability to focus on an object with both eyes. It allows for depth perception and the ability to perceive the world in three dimensions. A and B refer to the ability to focus, while D refers to color vision.