Why indoeuropean race is the only one where blonde hair as well as blue and green eyes are common?

better if you could refer to a book

Why indoeuropean race is the only one where blonde hair as well as blue and green eyes are common?

Pale skin, light eyes, and hair are all related to the amount of melanin in the skin. Melanin is the chemical that "pigments" our skin, and is a natural sun protectant. Melanin is important in the production of vitamin D, as exposure to sun light stimulates the liver to produce vitamin D. Too much or too little vitamin D can be harmful. Modern humans evolved in an equatorial environment, where there was a lot of sunlight, and darker skin could be naturally protected from the sun, and still allow for the production of adequate vit. D. As we migrated north, the reduced levels of sun exposure caused us to adapt, and our skin became lighter to accommodate for continued adequate production of vitamin D (lack of vitamin D can cause several severe bone diseases). Thus, Europeans developed less melanin in their skin, and since melanin also affects eye and skin color, this, and the fact that blue or green eyes, and blond and red hair are genetic mutations in their own right, is why you see lighter eyes and hair in Europeans.

Why indoeuropean race is the only one where blonde hair as well as blue and green eyes are common?

I think this is the kind of question that nobody has an answer to. We think pale skin evolved for ethnicities that were farther away from the equator. As for why skin AND eye colorm you got me.

Why indoeuropean race is the only one where blonde hair as well as blue and green eyes are common?

The Australian Aborigines are very dark with African skin colors and facial features, but frequently have blonde straight hair. But yes, I think they are still considered to be a race of people related more to Indoeuropean than African.

Oh, I also think that there are some African races that can have blonde or red kinky hair, but I'm not sure on that, I could be wrong.