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It is an adaptation to sunlight intensity, the risk of sunburn, and the need to manufacture vitamin D in the skin with the help of sunlight.
In Africa where modern humans evolved the sunlight intensity is strong and risk of sunburn is high, dark skin evolved to protect from sunburn and there was no problem making more than enough vitamin D.
As modern humans migrated out of Africa they entered areas with less sunlight, vitamin D deficiency diseases began to be a problem but the risk of sunburn was much lower, light skin evolved to raise vitamin D production.
The fact that we can now take vitamin D supplements and can use sunscreen to prevent sunburn has removed those selection pressures, so skin color differences will no longer be driven by natural selection. Instead they will most likely be controlled by personal preferences and sexual selection in the future.
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Why would a light switch have two black wires for power and two whites caped off?
Black represents Hot and White common. For the light to operate it needs a white and black wires. The switch box has two cables with a white and black wire plus a ground. One wire is from the supply and the other to the light. Connecting the whites just provides common directly to the light. The blacks go into and out of switch because it is the hot side that is being switched.
Why is a person that has one white parent and one black parent called black?
Due to the lack of pigment in the skin it associates with the color white. Whites are called white because they are fairly skinned people. (but i do not understand why all white people are called white. for one thing, we are not even white were more of a peachy tan colour [same as blacks, they are more of a brownish colour])
What if the new light fixture has 2 black wires and no white wire?
lights can be wired any way round, there is no positive or negative
Who was affected by segregation?
EVERYONE is affected by segregation! Blacks and whites!
Why are your whites of your eyes not white?
the whites of your eyes is in reference to the white arond ur eye
What is black privilege and white disadvantages?
an opportunity for blacks and a disadvantage for whites today.
Do some whites wish they where black?
Yes some do wish they were white but not only whites but some blacks wish they were white but many dont.
When the whites and blacks lived separately witch end did the blacks live on?
When the black and white people lived on separate sides the blacks lived on the east end and the whites lived on the the west end.
Was it illegal for a black to kiss a white Jim Crow laws?
Yes blacks and whites were segregated!
What was slavary?
Slavery is when white people take black people for slaves and blacks serve whites.
What did black and white people do when they used to fight?
When the black and white people used to fight they used to stand with whites on one side and (blacks) on the other side and they used to say "BLACK BLACK AND WHITE BLACK BLACK then the other word for blacks WHITE COMMON other word for blacks NOW LETS FIGHT." that what they used to do so yeah!:)
What did hiram Rhodes revels argue in the senate?
That whites and blacks should live together.
Are blacks better than whites?
Black and white people are equal. Neither is better than the other.
Are north Indians considered blacks or whites?
They are white... Black people have curly hair, and different mouth.
Is there more black then white?
In which country? There are different numbers of blacks vs whites in each part of the world.
What racial dynamics in American cities led to the continued separation of blacks and whites?
it was that they thought whites were better than blacks and also some people today think racially because of pokemon BLACK and WHITE they think white is for white people and black is for black people seriously some people are just plain idiotic
How were black Americans discriminated and segregated against in the southern states of America in the 1950's and 60's?
Blacks and whites were segregated socially and politically. Although not illegal (most places), interracial marriage was frowned upon, and whites typically did not hang around blacks (or vice versa). Blacks also had different jobs than whites, typically more hardworking for less pay. Blacks also had very little political liberties. Although granted the right to vote in 1865, blacks were hindered from voting (especially in the Southern US) in various ways until 1957. Segregation means separation, and whites and blacks were separated from many aspects of society. There were white and black neighborhoods, white and black schools, white and black restaurants, white and black bathrooms, etc.
