Question

which of the following is an example of osmosis? sugar diffuses in a glass of water. a potato gains mass when placed in purified water. ice melts and puddles on the floor. all of these are examples.

Explanation:

Osmosis is the movement of water molecules across a semi - permeable membrane from an area of lower solute concentration to an area of higher solute concentration. When a potato is placed in purified water, the potato cells have a higher solute concentration (compared to the pure water). Water moves into the potato cells (across the semi - permeable cell membranes) by osmosis, causing the potato to gain mass.
Sugar diffusing in water is simple diffusion (movement of solute particles from an area of high concentration to low concentration). Ice melting is a physical change (phase change from solid to liquid) and not related to osmosis.

Answer:

A potato gains mass when placed in purified water.