The Continued High Frequency of the Sickle Allele (S) of Hemoglobin

Multiple Choice

The continued high frequency of the sickle allele (S) of hemoglobin in Africans, in some Mediterranean populations, and in populations descended recently from Africans is a reflection of the response of human populations via _____ to a regional disease.

A) natural selection
B) sexual selection
C) artificial selection
D) genetic drift