Question

Diffusion will continue to occur between the inside and the outside of a cell until what is reached?

Answer 1

The correct answer is B (Equilibrium).

Diffusion will continue to occur until a state of equilibrium is attained.

Diffusion is the movement of molecules from areas of high concentration to areas of low concentration. The molecules will tend to move into any space available until they are evenly distributed  throughout this space.

When there is no longer a concentration gradient, there will be no net movement of molecules from one area to another. This state is known as dynamic equilibrium. 

Answer 2

Diffusion will continue to occur between the inside and the outside of a cell until equilibrium is reached. 

B. Equilibrium