Answer:
Passive process.
Explanation:
The cell membrane acts as the semi-permeable membrane that allows the movement of some selected particles only. The molecules may move along the concentration gradient and against the concentration gradient.
Passive transport may be defined as the movement of particles along the concentration gradient. No energy is required in this process and the particles are directly moves across the cell membrane. Small uncharged molecules can move by the passive transport.
Thus, the answer is passive process.
