(a) In human populations where HIV infection is common, are the frequencies of these "resistance genes" increasing, decreasing, or staying about the same? Explain your reasoning.

Increasing

Explanation:

This particular question or problem can be likened to a deductive reasoning. The viral disease known as HIV stand for Human Immunodeficiency Virus which is a disease that damages the immune system of anyone affected with the disease. The Human Immunodeficiency Virus goes through four main stages or steps that is to say the infection stage/step, the stages in which the symptoms does not show, the stages at which the symptoms start to show and the stage at which the Human Immunodeficiency Virus goes or turns to AIDS.

The frequencies of these "resistance genes" In human populations where HIV infection is common will increase. When Human Immunodeficiency Virus infection is common, people in  that particular society will develop more resistance to the virus and the survival of the fittest is taken into account as people with more resistance tends to be more healthier than the ones with less resistance.