Which hormone promotes the reabsorption of water from the kidneys back into the ecf by osmosis?

antidiurectic hormone.

Explanation:

physiologic effects of antidiuretic hormone

antidiuretic hormone binds to receptors on cells in the collecting ducts of the kidney and promotes reabsorption of water back into the circulation. in the absense of antidiuretic hormone, the collecting ducts are virtually impermiable to water, and it flows out as urine.

desert perennials often survive by remaining dormant during dry periods of the year, then springing to life when water becomes available. most annual desert plants germinate only after heavy seasonal rain, then complete their reproductive cycle very quickly.