Answer:
Having HIV/AIDS weakens your body's immune system. It destroys the white blood cells that fight infection. This puts you at risk for opportunistic infections (OIs). OIs are serious infections that take advantage of your weak immune system.
Explanation:
C. The question is hinting at the similarities between how single cellular organisms maintain homeostasis by regulating water levels the same way the kidney does for multi cellular humans.
You're right, it is D.
A theory can be changed if evidence is found that contradicts the current theory.
