What is the relationship between temperature and kinetic energy in a substance?

The correct choice highlights the fundamental relationship between temperature and the kinetic energy of particles within a substance. Temperature, a measure of the average kinetic energy of the particles in a material, directly correlates with how fast those particles are moving.

As temperature increases, the average kinetic energy of the particles also increases. This is because temperature is essentially a measure of the energy of motion of the particles; as they gain energy, they move more vigorously. This concept is central to the kinetic molecular theory, which describes the behavior of gases but applies to all states of matter. The increased motion results in more frequent and more forceful collisions between particles, which can explain changes in physical properties such as state changes (for example, melting or boiling) as temperature varies.

In contrast, the other options misrepresent this relationship. For example, suggesting that kinetic energy decreases with increasing temperature contradicts the foundational principles of thermodynamics and kinetic theory. Similarly, the idea that there is no relationship between temperature and kinetic energy ignores the established scientific understanding of how these concepts connect. Lastly, stating that kinetic energy remains constant as temperature decreases is also inaccurate, as it overlooks the direct dependence of kinetic energy on the thermal state of matter.