Which one of the following is the main function of renin and aldosterone:
A) they are produced whenever blood pressure rises and ultimately cause an increase in blood volume and blood pressure
B) they are produced whenever blood pressure rises and ultimately cause a decrease in blood volume and blood pressure
C) they are produced when blood pressure rises and have no long-term effect on blood volume and blood pressure
D) they are produced whenever blood pressure falls and ultimately cause an increase in blood volume and blood pressure
E) they are produced whenever blood pressure falls and ultimately cause a decrease in blood volume and blood pressure
Answer: D