Osmosis and Water Potential in Plant Cells

Steps:

• Water potential (ψ) is higher (less negative) in dilute solutions and lower (more negative) in concentrated ones; water moves from high to low ψ.
• Cell Y in 5% sugar (highest external ψ): gains water, so its ψ < external ψ (statement 1 correct).
• Cell X in 10% sugar (medium external ψ): loses water, so its ψ > external ψ, less negative (statement 2 correct).
• Cell Z in 17.5% sugar (lowest external ψ): loses water severely, so its ψ > external ψ, less negative (statement 3 correct).

Why A is correct:

• All statements match osmosis: water enters Y (cell ψ lower), exits X and Z (cell ψ higher/less negative) per water potential gradient definition.

Why the others are wrong:

• B omits 3, but Z loses water as external ψ is most negative.
• C omits 2, but X loses water to 10% solution.
• D omits 1, but Y gains water from 5% solution.

Final answer: A