Answer:
Step-by-step explanation:
a) This is to show that particles are in constant motion (and that matter is made of particles) with kinetic energy which enables particles of one matter to intermix with particles of another matter. this is known as diffusion. For example, the fragrance of a burning incense stick could be felt even at the farther end of the room because particles from the incense stick rise and intermix with the particles of air. T hey diffuse and spread all over the room.
b) Brownian motion is a constant zig-zag motion particles undergo. This can be noticed in a colloidal solution. particles of a colloidal solution remain active as they are charged with the same charge (all the particles of a certain solution carry the same charge). This causes each of them to repel from each other thus putting them into constant motion (kinetic energy). Thus, this too shows that particles are in constant motion (and that matter is made of particles).