Why are colors blended in a rainbow

So if you mix all the rainbow colors together, it will be white again. Light is Additive, meaning when you mix all colors of the visible spectrum you get white light. Pigment on the other hand is subtractive and adding all primary colors gets you browns and blacks.

Explanation:

i think it's about 10 mins.

actually i think that's wrong, but i don't know how to delete this.

but who knows it might be right.