Question

for osmosis to occur, ____. pure water must be on one side of the membrane only solutes can pass through the membrane a concentration gradient cannot exist a selectively permeable membrane must be present cellular energy must be expended

Explanation:

Osmosis requires a selectively permeable membrane (allows solvent but not solute passage) and a concentration gradient. Pure water isn’t mandatory; solutes can’t pass; gradient is needed; no energy is used. The only essential condition here is a selectively permeable membrane.

Answer:

a selectively permeable membrane must be present