Submitted the document for the case study in “Changing Allele Frequencies” and it contained the following:

Explained why the increased prevalence of sickle-cell disease among African Americans has more to do with the environmental factors than the skin color or other phenotypes used to define races. (10)
Described other examples of balanced polymorphism. (10)
Identified a population group (other than African Americans) with a high prevalence of sickle-cell disease. (10)
Listed six genetic diseases more common among Ashkenazi Jews than among other population groups. (10)