The problem of univariance refers to the fact that:. a. we have three types of cones in our visual system.
b. an infinite set of different wavelength-intensity combinations can elicit the same response from a single type of photoreceptor.
c. an infinite numbers of colors exist in the real world.

b. an infinite set of different wavelength-intensity combinations can elicit the same response from a single type of photoreceptor.

Explanation:

The principle of univariance is based on the fact that a visual receptor cell can be excited by different wavelength-intensity combination, so that the brain cannot know the color of a certain point of the retinal image. This means that the same visual receptor cell might not be able to tell the difference between a dim light and a bright or even between lights of different colors.

in 342 bc j._c. egypt fell into the hands of the persians, under the reign of nectanebo ii

greek city-states unite in a revolt against the persian empire at the beginning of the fifth century bc. j.-c  

from the year 660 or 659 bc ad, cyrus preached the revolt against the medes to deliver the persians.