Answer :
Answer:
The correct option is' a'.
Diffusion is the movement when molecules move from higher concentrated area to lower concentrated area.
Explanation:
When a substance moves from higher concentrated area to a lower concentrated area, is called as diffusion.
It mainly occur in liquid and gaseous substance as their particle can easily move from one place to another.
Diffusion is important for living being as water enters into the plant body through the process of diffusion and during respiration, when the concentration of carbon dioxide is high then it diffuse out through the cell membrane and enters into the blood.