People often seem to think of the world's people as if they can be divided up into three main groups: crudely white, black and yellow. In fact, scientists say it's nonsense because things are really not that simple.

The idea that Africa has only very dark skinned black people forgets that there are many with lighter skins north of the Sahara desert. It also forgets that people from different parts of Africa (while they might all have dark skin) look very different from each other in other ways.

Another example that the 'three different types of people' idea doesn't work is with people from around India. They have dark skin (though it's much lighter in the north, and people in the northern mountains often have blue eyes too) but their faces are very different from Africans. Then there's Australians, who have dark skin but hair like Europeans and Indians. As for Europe, many people in Spain look pretty much like people from north Africa, some Italians are blond and some Norwegians are dark. Confused? Exactly. Genetic differences between people do not fit into neat little boxes that match up to countries.