Answer the following question given this paragraph: 

No doubt you already have a good idea of what temperature is. You might say that it’s how warm or cool something feels. In physics, temperature is defined as the average kinetic energy of the particles of matter. When particles of matter move more quickly, they have more kinetic energy, so their temperature is higher. With a higher temperature, matter feels warmer. When particles move more slowly, they have less kinetic energy on average, so their temperature is lower. With a lower temperature, matter feels cooler.


Q: In physics, what is defined as the average kinetic energy of the particles of matter?

 Choices:

- density

- friction

- magnetism

- temperature

A:
temperature
