In some regions where malaria is endemic, the frequency of the sickle-cell allele is as high as 15% due to heterozygous advantage for increased resistance to malaria. in such an area, what is the expected frequency of individuals who are healthy and have resistance to malaria?

Explanation: Why are there higher frequencies of the sickle cell allele in areas where malaria is more prevalent? In areas where malaria is endemic, the presence of the sickle cell allele in the heterogeneous state improves the fitness of individuals. However, convincing evidence indicates, in areas with persistent malaria outbreaks, individuals with the heterogeneous state have a distinct advantage (and this is why individuals with heterogeneous alleles are far more common in these areas). Those with the benign sickle trait possess a resistance to malarial infection.