Question

what does it mean when substances move down a concentration gradient? choose the best answer. a they move from areas where there are lots of particles to areas where there are few particles. b they move from areas with lots of water to areas where there is little water. c they move from one side of a cell membrane to the other. d they move from areas where there are a lot of particles to areas where there are few particles

Explanation:

Diffusion is the movement of substances from an area of high - concentration (where there are lots of particles) to an area of low - concentration (where there are few particles). This is what is meant by moving "down a concentration gradient".

Answer:

A. They move from areas where there are few particles to areas where there are lots of particles