According to the potential/kinetic theory, what is the nature of particles?

The correct answer is based on the understanding that, according to the kinetic molecular theory of gases, particles are always in constant motion. This theory describes how gas particles, for instance, behave; they move rapidly and randomly, colliding with each other and with the walls of their container.

These rapid movements, which are influenced by temperature, contribute to the properties of gases, such as pressure and volume. In a gaseous state, particles exhibit this constant motion, allowing them to fill their container uniformly and disperse.

While the terms "static motion" and "intermittent motion" imply a lack of consistent energy or willful displacement, and "random motion" could describe the unpredictability of a particle's path, it does not capture the essential aspect of constant motion across all particles in kinetic theory. Constant motion highlights that particles are perpetually moving unless they are at absolute zero, where they theoretically experience no motion whatsoever. Thus, considering all these aspects, the characterization of particles as constantly in motion aligns perfectly with the principles laid out in kinetic molecular theory.