Final answer:
The kidneys help regulate blood pressure by adjusting blood volume through various mechanisms. They produce a protein called angiotensin to constrict blood vessels and retain sodium and water, helping to maintain normal blood pressure.
Step-by-step explanation:
The kidneys help regulate blood pressure by adjusting blood volume. When blood pressure drops too low, the kidneys produce a protein called angiotensin, which constricts blood vessels and signals the body to retain sodium and water, helping to restore normal blood pressure. The kidneys also play a role in maintaining water balance in the body, adjusting the production of urine based on the body's water levels.