Similarly, a plant or animal cannot squander all its energy on growing a big body if none would be left over for reproduction, for this is the surest way to extinction.

同样，如果一种植物或动物没有留下任何可以繁殖的后代，它就不能把所有的能量浪费在使自己变得更强壮上，因为这是最可能走向灭绝的方式。