Individuals That Are Heterozygous for Sickle-Cell Anemia Are More Resistant

Multiple Choice

Individuals that are heterozygous for sickle-cell anemia are more resistant to malaria than those that do not have a sickle-cell allele. Why does the sickle-cell allele not become fixed in the population?

A) Individuals homozygous for the sickle-cell allele do not have the same resistance to malaria.
B) Individuals that are homozygous without the sickle-cell allele produce more offspring than those with the sickle-cell allele.
C) Individuals that are homozygous for the sickle-cell allele have sickle-cell anemia, and are at a fitness disadvantage.
D) Individuals heterozygous for the sickle-cell allele die earlier than either of the homozygous individuals.
E) Analysis indicates the allele is becoming fixed in the population.