Which statement about osmolality and water movement is true?

Which statement about osmolality and water movement is true?

• A. Lower osmolality dictates water movement between compartments.
• B. Water movement is driven by active transport of solutes.
• C. Higher osmolality dictates the movement of water between compartments.
• D. Osmolality has no influence on water distribution.

Answer: (C)

Water moves by osmosis toward the side with higher solute concentration, i.e., higher osmolality. This gradient pulls water across membranes to balance solute levels, so the direction of water movement is dictated by higher osmolality in the target compartment. Active transport of solutes isn’t required for this process—it’s a passive movement driven by the osmotic gradient. Osmolality strongly influences how water distributes between compartments; saying it has no influence ignores the basic mechanism of osmosis.

Water moves by osmosis toward the side with higher solute concentration, i.e., higher osmolality. This gradient pulls water across membranes to balance solute levels, so the direction of water movement is dictated by higher osmolality in the target compartment. Active transport of solutes isn’t required for this process—it’s a passive movement driven by the osmotic gradient. Osmolality strongly influences how water distributes between compartments; saying it has no influence ignores the basic mechanism of osmosis.