The picture shows molecules inside and outside of a cell. Assume that the molecules can pass through the cell membrane.

Question

Which best describes what will happen?

The molecules inside the cell will move out of the cell until they are all outside of it.
The molecules outside of the cell will move into the cell until they are all inside it.
The molecules inside the cell will expand in size until the cell is large enough to hold all the molecules.
The molecules outside of the cell will move into the cell until the number of molecules on both sides of the cell membrane is equal.

Answer 1

The best description of what will happen is:

The molecules outside of the cell will move into the cell until the number of molecules on both sides of the cell membrane is equal.

This process is known as diffusion, where molecules move from an area of higher concentration to an area of lower concentration until equilibrium is reached.