Estrogen's are the female sex hormones. <span />
Evolutionary Theory of Aging describes t<span>he view that natural selection has not eliminated many harmful conditions and nonadaptive characteristics in older adults. N</span>atural selection is linked to reproductive fitness, which is present only in the earlier part of adulthood. According to evolutionary theory, possibly if some disease occurred earlier in development, it might have been eliminated many centuries ago.
D?!? Let me know if you get it right
The answer would be <span>oxygen.</span>
