Answer:
ok, so if an hiv is a virus that attacks the immune system, how does that affect you?
if your immune system is weak in a moment, bad bacteria can enter your blood and cause problems and weaken your immune system even more.
its really bad for a person's health, it weakens your immune system so your body has a tougher time fighting against a virus.
Normal, clean rain has a pH value of between 5.0 and 5.5, which is slightly acidic. However, when rain combines with sulfur dioxide or nitrogen oxides—produced from power plants and automobiles—the rain becomes much more acidic. Typical acid rain has a pH value of 4.0.
Out of the choices given, the mechanisms that drives evolution is natural selection. The correct answer is B, natural selection.
