The frequency of heterozygosity for the sickle cell anemia allele is unusually high, presumably because this reduces the frequency of malaria. Such a relationship is related to which of the following? A. Mendel's law of independent assortment B. Mendel's law of segregation. C. Darwin's explanation of natural selection. D. Darwin's observations of competition. E. The malarial parasite changing the allele.

C. Darwin's explanation of natural selection

Explanation:

According to Darwin, natural selection selects for traits that are more adaptable to an environment and individuals with such traits tend to reproduce and contribute more offspring to successive generations.

As the environment keeps changing, organisms keep trying to adapt to the changes. Those who are able to adapt flourish more within the environment while the weak ones gradually get replaced in the population.

In the case of sickle cell heterozygosity and malaria; individuals that are heterozygous for the sickle cell trait are generally known to be less prone to malaria. Hence, this becomes a selection advantage over individuals with other genotype forms. Heterozygous individuals thus contribute more offspring into the population than other genotype forms according to natural selection law.

The correct answer is C.