In the past, natural selection guaranteed that only fit humans survived to reproduce.
(natural selection; guaranteed; that only fit humans survived to reproduce; T:In the past) Context(natural selection guaranteed,List([13, 41))):(only fit humans; survived; to reproduce) Context(natural selection guaranteed only fit humans survived,List([13, 71))):(only fit humans; survived to reproduce; )
natural selection guaranteed,List([13, 41)) natural selection guaranteed only fit humans survived,List([13, 71))
natural selection only fit humans only fit humans
guaranteed survived survived to reproduce
that only fit humans survived to reproduce T:In the past
to reproduce