Answer:
Collecting duct
Explanation:
Antidiuretic hormone or ADH is the hormone maintains the water concentration in the blood.
The ADH is secreted by the neurons in the hypothalamus which is released into the blood when the water level of blood decreases. The ADH then binds to the ADH receptors in the collecting tubule of the nephron where it inserts the aquaporins into the membrane of the collecting tubule.
The aquaporins allow the reabsorption of water in the blood and thus maintains the water concentration in the body.
Thus, collecting duct is the correct answer.
