Answer the following question given this paragraph: 

The radiative zone is the next layer out. It has a temperature of about 4 million degrees C. Energy from the core travels through the radiative zone. The rate the energy travels is extremely slow. Light particles, called photons, can only travel a few millimeters before they hit another particle. The particles are absorbed and then released again. It may take 50 million years for a photon to travel all the way through the radiative zone.


Q: What do you call the light particles that travel through the radiative zone?

 Choices:

- neutrons

- ions

- electrons

- photons

A:
photons
