Northern elephant seals were hunted to the point that their population size was reduced to as few as 20 in the late 1800s. Since then, their populations have rebounded to over 30,000. However, the genetic diversity is significantly reduced in the rebounded population of elephant seals. What explains this lack of genetic diversity in a population of 30,000? A) Natural selection reduced genetic diversity as those that survived had the most favorable traits. B) Artificial selection reduced genetic diversity, as humans chose the preferred phenotypes of the elephant seals that survived in the 1800s. C) Population bottleneck reduced genetic diversity, as the gene pool of the 30,000 elephant seals resulted from the few alleles present in the 20 bottleneck survivors. D) Gene flow decreased genetic diversity, as significant numbers of elephant seals migrated to remote locations far from humans, leaving only a limited genetic diversity.

Archeologists have discovered three sites showing conclusive evidence for the mastery of fire in tanzania, from a period slightly after the time that homo habilis was present in africa. these sites clearly were founded by homo erectus, the descendent species of homo habilis that migrated north, out of africa and into asia. homo erectus was known to have mastered fire, from ample evidence at sites in asia. there is no reason to attribute mastery of fire to homo ergaster, the descendent species of homo habilis that remained in africa.which of the following is an assumption on which the argument depends? (a) before their migration, homo erectus occupied african territory as far south as tanzania.(b) the strain of migration provided the selective pressure motivating homo erectus‘ mastery of fire.(c) homo ergaster would not have derived as much benefit from the mastery of fire as did homo erectus.(d) homo ergaster inherited all cultural knowledge from homo habilis, a species that did not have mastery of fire.(e) homo ergaster did not occupy regions as far south as tanzania until well after the time of these three sites.