Question

question 4
what is the best description of diffusion across a cell membrane?
materials move across the cell in both directions
materials move from inside the cell to outside the cell
materials passively move from a high concentration to a low concentration
materials passively move from a low concentration to a high concentration

Explanation:

Diffusion is a passive - transport process. In the context of a cell membrane, substances move down their concentration gradient, from an area of high concentration to an area of low concentration without the use of energy.

Answer:

materials passively move from a high concentration to a low concentration