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

Keeping in mind the life cycle of bacteriophages, consider the following problem: during the reproductive cycle of a temperate bacteriophage, the viral dna inserts into the bacterial chromosome where the resultant prophage behaves much like a trojan horse. it can remain quiescent, or it can become lytic and initiate a burst of progeny viruses. several operons maintain the prophage state by interacting with a repressor that keeps the lytic cycle in check. insults (ultraviolet light, for example) to the bacterial cell lead to a partial breakdown of the repressor, which in turn causes the production of enzymes involved in the lytic cycle. as stated in this simple form, would you consider this system of regulation to be operating under positive or negative control?

In what part of the body does the most muscle activity happen?

When making her coffee, mrs. jenkins likes to stir in some cream and sugar to give it a pleasant flavor. the ingredients, when combined like this, form a