In Central Africa, the Frequency of the Sickle-Cell Allele Has

Multiple Choice

In central Africa, the frequency of the sickle-cell allele has remained stable over the years because the allele protects against malaria. In the United States, malaria was eradicated by eliminating the mosquito that spreads the disease. The decreasing frequency of the sickle-cell allele in African Americans since malaria was eliminated in the United States is an example of

A) stabilizing selection.
B) the founder effect.
C) directional selection.
D) genetic drift.
E) disruptive selection.