So they respond by releasing hormones that stimulate the body to retain sodium and water. Blood vessels fill with additional fluid, and blood pressure goes up. The narrowing in one or both renal arteries is most often caused by atherosclerosis, or hardening of the arteries.
Answer:
C. Independent variable
Explanation:
The independent variable in an experiment is the variable that the experimenter manipulates or changes in order to effect a measurable response in the dependent variable.
According to this question, an experiment is conducted to determine what concentration of disinfectant is most effective in killing bacteria. The independent variable is the CONCENTRATION OF DISINFECTANT because it is the variable being changed or manipulated.