字幕列表 影片播放 列印英文字幕 It's AumSum Time Why do we have different skin colors? It is because of a pigment called melanin and ultraviolet radiation of the sun. Confused? Obviously. Alright. I'll explain. Millions of years ago, people living near equator received a lot of sunlight and ultraviolet radiation. Now, ultraviolet radiation is actually absorbed by our skin to produce Vitamin D. But excess radiation can damage our skin cells. Hence, the skin of these people produced more melanin to block the excess ultraviolet radiation. Thus, over time. These people and their succeeding generations adapted to have a higher level of melanin in their skin. Making their skin darker. However, people living away from equator received less sunlight and less ultraviolet radiation. Hence, in order to absorb sufficient ultraviolet radiation and produce the essential Vitamin D. These people and their following generations adapted to have a lower level of melanin. Thus making their skin lighter.
B2 中高級 美國腔 為什麼我們有不同的膚色?| 奧琛時間 (Why do we have different skin colors? | It's AumSum Time) 733 19 wwzz1207 發佈於 2021 年 01 月 14 日 更多分享 分享 收藏 回報 影片單字