As your lens hardens through aging, you may have trouble with

If a researcher finds that one drop of perfume diffused through a three-room apartment is the minimum amount of stimuli needed to notice the scent, then this would be a test of one's

"Packets" of light waves are referred to as

Color is largely determined by the

Light bends as it passes through substances of different densities, a process known as

The image projected on the retina is

Full dark adaptation, such as going from constant light to sudden darkness when turning out one's bedroom lights, takes about _____ minutes.

Thomas Young's theory of color vision

Cones are the special cells responsible for