他表示：在鼠类研究中，人们仅仅清点已死动物的数目，而不会去分析哪些死亡与衰老无关。

In mouse studies, people just count the number of dead animals without asking which deaths might be unrelated to aging, he said.

youdao

And one of the reasons that's most responsible for that is that humans aren't dying at as young an age from infectious diseases as they did three or four hundred years ago.

最重要的一个原因就是,人们不会在年轻的时候死于传染性疾病,而这在三四百年前确实会发生

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