In the 1940s, the scientist J. B. S. Haldane linked many human red blood cell disorders with the tropical regions where malaria occurs. Haldane hypothesized that the widespread
presence of these red blood cell disorders as well as traits that protect individuals from
malaria were the result of natural selection. Haldane's hypothesis was later confirmed by the
research of A. C. Allison.
The resistance to malaria carried by individuals in areas where malaria is widespread is the
result of -
A a vaccine against malaria
B the individuals' genetic composition
C antibiotic medications
D the individuals' behavior in avoiding those with the infection