Your cousin just started a part-time job at a blood bank. He tells you that a surprisingly large number of Native Americans come in to donate blood. You explain to him that, based on what you learned in physical anthropology class, this is not all that surprising because
A. owing to a founder effect, many Native American populations have high frequencies of the O blood type.
B. gene flow between Native Americans and European Americans but not vice versa means that Natives are the universal donors.
C. the AB blood type was selected for in the Native American population as a genetic adaptation in response to the smallpox that Europeans brought.
D. many Native American lands are on toxic waste dumps that cause a higher frequency of mutations and result in a high proportion of people with the A blood type.
Answer: Owing to a founder effect, many Native American populations have high frequencies of the O blood type.