Concept:The continual, random motion of molecules is best shown by the erratic movement of tiny particles in a fluid.
Explanation:Brownian motion is the haphazard, jittery movement of visible microscopic particles, such as pollen grains, suspended in a liquid or gas.
These particles are constantly struck by invisible molecules moving around them.
Because the collisions occur from random directions, the particles change speed and direction frequently.
The motion never stops, which proves that the molecules themselves are in continuous, never-ending motion.
Answer:C. Brownian Motion