Answer:
random internal motion of atoms and molecule
Step-by-step explanation:
The primary cause of diffusion is the random internal motion of atoms and molecules.
Randomness of atoms and molecules results in diffusion.
- Diffusion is the movement of particles from a region of high concentration to that of lower concentration.
- Substances often tend to spread out over the concentration gradient.
- Therefore, they have this propensity to be randomized.