8. 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 individual's' genetic composition
c. Antibiotic medications
d. The individuals' behavior in avoiding those with the infection