Nothern people need more effetive sunlight to synthesize Vitamin D,

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送交者: habpi 于 2008-10-11, 23:37:44:

回答: 太简单了:靠近赤道经常晒太阳,晒黑了;靠近北极,阳光少,皮肤白 由 找老婆专用ID 于 2008-10-11, 23:23:31:

thus lighter skins serve them well.
But too much exposure can harm the DNA and cause skin cancer - the darker skin of tropical people is more protective.

Is there anything else?



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