A potassium ion gradient is set up in insect Malpighian tubules through an active transport process. As a result, potassium concentration is higher in the lumen of the tubules than in hemolymph. How would the potassium gradient affect water movement?
A) Water would be forced out of the lumen of the Malpighian tubules through an osmotic gradient.
B) The potassium gradient would have no effect on water movement.
C) There would be a net movement of water into the lumen of the tubules.
D) Water would be conserved, forming a hypertonic solution in the Malpighian tubules.
Answer: C