Answer:
ADH
Explanation:
facultative water reabsorption - The water withdrawn from the plasma filtrate as a regulated negative feedback control of hydration status under the influence of ADH = antidiuretic hormone; this water reabsorption occurs primarily in the loops of the nephrons, particularly the juxtamedullary nephrons; the quantity of water reabsorbed in this fashion represents from ~1% to ~10% of the total water reabsorbed by the renal tubules.
