Define Countercurrent Multiplication as It Occurs in the Kidneys

Multiple Choice

Define countercurrent multiplication as it occurs in the kidneys.

A) The exchange of substances in the adjacent limbs of the nephron loop containing fluid moving in opposite directions.
B) The exchange of substances in the adjacent limbs of the nephron loop containing fluid moving in the same directions.
C) The cycling of urea from the collecting duct to the nephron loop and back.
D) The bulk reabsorption of substances in the proximal convoluted tubule and the bulk movement of water due to osmosis.
E) The secretion of ions in response to hormones in the distal convoluted tubule.