Blue light and yellow light combine to produce white light because
a. they absorb each other s wavelengths.
b. blue, yellow, and white are primary colors.
c. they are complementary colors of light.
d. they are both primary colors of light.

Blue and yellow light combine to produce white light because they are complementary colors of lights.
When you say complementary colors, it refers to a combination of 2 colors that when mixed, they fade out their color. That's why when blue light and yellow light are combined they produces white light.

The answer is b.the gaseous state is electrically positive, while the plasma state is electrically negative.