In order to distinguish between wavelengths independent of light intensity, one must have at least _____visual pigment(s).
A) one?
B) two
C) three
D) four

Question

Quizplus · Accepted Answer

Two visual pigments are necessary for color vision because they allow for comparison and distinction between different wavelengths of light. A single pigment would only allow for detection of light intensity, not wavelength. Three or four pigments are present in some animals, such as birds and some primates, but two is sufficient for humans.

In Order to Distinguish Between Wavelengths Independent of Light Intensity