Final answer:
Aldosterone and antidiuretic hormone act to increase water conservation in the body by promoting sodium reabsorption and water reabsorption respectively, resulting in reduced urine volume and maintained plasma osmolarity.
Step-by-step explanation:
Aldosterone and antidiuretic hormone (ADH) are crucial in regulating the body's water balance. Aldosterone works to conserve water in the body by increasing the reabsorption of sodium in the distal tubule, which in turn leads to water retention. In response to signals such as decreased blood sodium, reduced blood volume, or lowered blood pressure, aldosterone promotes Na+ recovery and potassium excretion. On the other hand, ADH primarily acts on the collecting ducts of the kidneys to promote water reabsorption, reducing urine volume and helping to maintain plasma osmolarity and blood pressure. The synergistic actions of these hormones result in increased water conservation.
The correct response to the student's question about what aldosterone and antidiuretic hormone act to increase is: A. water conservation.