What is the reason behind the similarity of the Chinese form?

What is the reason behind the similarity of the Chinese form?

We often wonder about the reason for the similarity in the shapes of the peoples of the yellow race and the similarity of their eyes, which makes us not distinguish one person from the other, so what is the reason behind that?

The reason behind the drawn eyes of the yellow peoples such as Japan, China and Korea .... It is not a congenital malformation as some think, but rather a genetic mutation that occurred due to their geographical presence, as the skin folds that cover the eye are to protect it from very low temperatures in cold areas and also to protect it from ultraviolet rays and harmful sunlight in tropical areas.

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