The Persistence of the Sickle-Cell Anemia Allele in Some African

Multiple Choice

The persistence of the sickle-cell anemia allele in some African populations is the result of ____.

A) ​a high rate of mutation of the normal allele to the sickle-cell anemia allele
B) ​the advantage of the heterozygous form over the homozygous forms
C) ​nonrandom mating
D) ​a decline in the occurrence of malaria in Africa
E) ​genetic drift