据书上说，人类原来也是有尾巴的，后来大约是退化掉 了。尾巴为什么会退化?据说是没有用了。没有用的东西是 应该退化的，但是为什么盲肠不但没用反而有害却退化得 这么慢，尾巴却退化得那么快?何况人类的尾巴难道真的是 没有用吗?如果你允许，我愿意花一天甚至更多的时间来列 举人类尾巴的作用。 如果人类有尾巴，就可以尾巴卷着尾巴，而不必手牵 According to the book, humans also had tails, and they were later degenerated. Why is the tail degenerating? It is said to be useless. The useless thing should be degraded, but why is the cecum not only useless but harmful but degenerate so slowly, the tail is degenerate so quickly? Isn’t the human tail really useless? If you allow, I’m willing to spend a day Even more time to enumerate the role of the human tail. If humans have tails, they can wrap their tails on their tails without having to hold hands.