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Why are black hands black?

This is a normal phenomenon.

My family immigrated to Canada, and I often see black people here. Not to say that you can't get sunburned, because the skin is different, and the skin on the back of your hand is different from that on your palm.

If you don't believe me, you can have a look at yours. Careful observation shows that the color of the palm is lighter than that of the back of the hand.