Osmotic Equilibrium in Potato Cells

Steps:

• Potato size unchanged indicates no net water movement, so osmosis is at equilibrium.
• Equilibrium occurs when water potentials are equal, preventing net flow.
• Sucrose concentration affects solution water potential, but potato's is due to solutes inside cells.
• Thus, equal water potentials mean no size change, regardless of exact concentrations.

Why D is correct:

• Water potential equality defines osmotic equilibrium, where net water movement stops (ψ_potato = ψ_solution).

Why the others are wrong:

• 1: Concentrations may differ; potato water potential includes pressure and solute effects, not just sucrose concentration.
• 3: Water molecules still diffuse both ways, but net movement is zero at equilibrium.

Final answer: D