How many separate colors can the human eye distinguish?

Up to 10 thousand
Up to 10 million
Up to 100 million

Cones help us see in scotopic low light (gray) conditions, while rods help us see in photopic bright light (color) conditions.

True
False

The photoreceptor cells known as rods contain the photopigment iodopsin, which enables us to see in low light levels.

True
False

Trichromatic theory proposes that:

Three types of photoreceptor cones send specific colors to the brain.
Four types of photoreceptor cones send specific colors to the brain.
There are three combinations of color signals.

Opponent theory proposes that:

Three types of photoreceptor cones send specific colors to the brain.
Four types of photoreceptor cones send specific colors to the brain.
There are three combinations of color signals.

What color vision deficiency/deficiencies are most common?

Protanopia, or lack of red photopigment
Tritanopia, or lack of blue photopigment
Deuteranopia, or lack of green photopigment
Both 1 and 3