The cell membrane is a thin layer that wraps around the cytoplasm.
In a plant cell, the cell wall surrounds the cell membrane. Most substances can pass through the cell wall. But when these substances reach the cell membrane, only some of them are able to enter the cell.
Select the part whose main job is to control which substances enter and leave a plant cell.
A: cell membrane
B: cytoplasm
C: mitochondria
D: vacuole