Question

diffusion is most useful when...cells need something that cannot move in through the cell membrane, and they have more of it than their outside environment.cells need something that cannot move in through the cell membrane, and they have less of it than their outside environment.cells need something that can move in through the cell membrane, and they have more of it than their outside environment.cells need something that can move in through the cell membrane, and they have less of it than their outside

Explanation:

Diffusion is the movement of molecules from an area of higher concentration to an area of lower concentration across a semi - permeable membrane (like the cell membrane). For diffusion to occur, the substance must be able to pass through the cell membrane (so it can move). And it moves from where there is more (higher concentration outside the cell if the cell needs it) to where there is less (inside the cell if it has less).

Answer:

cells need something that can move in through the cell membrane, and they have less of it than their outside environment.