With regard to water excretion:

• A. 280 l is filtered per day
• B. it is impossible to excrete more than 23 l/day
• C. most regulation is via manipulation of the gradients along the loop of Henle
• D. vasopressin acts to insert water channels into the basolateral cell membrane of the collecting ducts
• E. water reabsorption in the collecting ducts can alter by a factor of 2.5 dependent on the presence of vasopressin