Final answer:
Temperature measures the average kinetic energy of the particles in a substance, affecting states of matter and chemical reaction rates.
Step-by-step explanation:
Temperature measures the average kinetic energy of the particles in a substance. It is a crucial parameter used to determine how hot or cold an object is relative to another. Specifically, as particles in a substance absorb heat, they move faster, and this increase in motion translates to a higher temperature. Conversely, a decrease in particle motion indicates a lower temperature. This is reflective of the fact that temperature is an intensive property, meaning it is not dependent on the amount of substance present. Therefore, the correct answer to what temperature measures is number 5: the average kinetic energy of particles in a substance.
Additionally, temperature affects various chemical and physical phenomena. For example, substances change states, like moving from solid to liquid, when there is an increase in temperature. Furthermore, an increase in temperature often leads to faster chemical reactions, while lower temperatures can help maintain the stability of sensitive materials like enzymes.