1, black people belong to black race, so they are born with black skin. Africa is located in the tropics, which is dry all the year round, with long direct sunlight time and strong ultraviolet radiation intensity. In addition, through gene selection, its black congenital has been gradually determined.

2. Black people originated in tropical equatorial regions, and were exposed to the sun for a long time, with high temperature and strong ultraviolet rays within one year. If you want to live comfortably in this environment, you must have special skills.

3. Black people have evolved black skin through long-term evolution. Dark skin can intercept ultraviolet rays on the skin surface, prevent ultraviolet rays from damaging the internal structure of the skin and reduce the occurrence of skin cancer.

Extended data:

Black people are black people, also known as black people, and black people account for 15% of the world population. Nigro-Australian race and equatorial race are people divided according to heritable physical characteristics, which is one of the human classification theories.

Black people generally have dark skin, wavy or curly hair, dark eyes, wide and flat nose, low or medium nasal root, small nasal process, large nostril diameter, lip process, wide mouth, thick lips, and little beard and body hair.

The racial classification of blacks mainly includes Sudanese blacks, Bantu blacks (both of which account for the vast majority of African blacks), Koisan blacks, Cuscito blacks (mixed-race) and Australian aborigines.

Before and during the Middle Ages, they were mainly distributed in sub-Saharan Africa. Later, because of imperialism and mercantilism in European countries, a large number of blacks were forced to be sent to South America and North America as slaves.

Negro was once used as a name for a black man in English, but it was originally a "black man" in Spanish, but it had a strong contempt. Some black groups with a long history still use this word today, such as the African American University Foundation.

The common name of American media is: African-Americans. Black (black) is also acceptable, and nigger (low-level) is completely derogatory. However, some black people also use this word to address each other.

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