Free Flashcard From Biology I Chapter 23
Adult male humans generally have deeper voices than do adult female
humans, as the direct result of higher levels of testosterone causing
growth of the larynx. If the fossil records of apes and humans alike
show a trend toward decreasing larynx size in adult females, and
increasing larynx size in adult males, then A) sexual dimorphism was developing over time in these species. B) intrasexual selection seems to have occurred.C) the "good genes" hypothesis was refuted by these data.D) stabilizing selection was occurring in these species concerning larynx size.E) selection was acting more directly upon genotype than upon phenotype.