(Solved): The trait causing sickle cell anemia evolved in Sub-Saharan equatorial Africa as it gave increased ...

The trait causing sickle cell anemia evolved in Sub-Saharan equatorial Africa as it gave increased survivability to malarial parasites. The sickle cell shape of the red blood cell causes severe circulation problems in individuals homozygous for the trait but individuals that are heterozygous get malarial resistance and only some circulatory problems. In the United States, the parasite that causes malaria is not present, but the sickle-cell trait is present in people of African descent. What should be happening to the sickle-cell allele in the United States, and what should be happening to it in equatorial Africa? Select one: a. directional selection in U.S.; stabilizing selection in Africa b. disruptive selection in U.S.; directional selection in Africa c. disruptive selection in U.S.; stabilizing selection in Africa d. stabilizing selection in U.S.; disruptive selection in Africa e. directional selection in U.S.; disruptive selection in Africa