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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.
What else can I help you with?
Do blacks and whites have same number chromosomes?
yes they do, and the colour of someone's skin has nothing to do with a different number of chromosomes. difference species have difference numbers of chromosomes yes blacks and whites have the same number of chromosomes Yes
Why is a person that has one white parent and one black parent called black?
Historically, in the United States, the "one-drop rule" classified individuals with any amount of African ancestry as black. This rule was used to uphold racial segregation and hierarchy. As a result, biracial individuals with one white parent and one black parent were typically labeled as black.
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.
Did blacks have whit or black doctors?
Historically, black individuals typically had black doctors due to racial segregation that limited access to medical care from white physicians. Today, individuals of all races have access to medical professionals of various backgrounds.
What if the new light fixture has 2 black wires and no white wire?
If the new light fixture has 2 black wires and no white wire, it likely means that the fixture is designed to be connected to a circuit where the white wire has been designated as the hot wire instead of the black wire. Make sure to double check the wiring and consult a professional if you are unsure.
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 north Indians considered blacks or whites?
They are white... Black people have curly hair, and different mouth.
Are blacks better than whites?
Black and white people are equal. Neither is better than the other.
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.
Why did whites decide on the blacks for slaves?
because the black not as good as the whites, so the whites catch then black and send them to work for the whites
