How many nutural colors are there in the world?

Answer 1

I assume you mean "natural", but even so the question is meaningless.

The human eye is capable of distinguishing between perhaps a few million colors. This is complicated by the fact that two people can disagree on whether two items are the same color or different colors, and by the fact that outside of some VERY broad generalizations ("blue" vs "red"), most of these either don't have names or people disagree on what the name should be. It may be amusing to go to bridal stores and ask if they have bridesmaid's dresses in "mauve" ... even at the same store, you'll see everything from brown to pink to light purple described as "mauve." (Other fun colors are "taupe" and "dusty rose," where different dressmakers disagree substantially on the relative proportions of dust vs. rose. Expect both of these to overlap substantially with "mauve.")