Osmoregulation in the Shark

Osmoregulation in the Shark
-Refer to the accompanying table. Because the shark rectal gland functions only when ATP molecules are present, what can you infer about the movement of Na+, K+, and Cl−?

A) Movement of these ions from circulation into the rectal gland is an active process.
B) Movement of these ions takes place from a region of higher concentration to a region of lower concentration.
C) These ions move into the rectal gland down their concentration gradient.
D) The rectal gland is unable to concentrate these ions.