According to the Scitable website by Nature Education, Volvox is a type of multicellular organism in the green algae family, and it does not eat anything. Rather, it undergoes a process known as photosynthesis in order to obtain energy from sunlight and convert it into the energy needed to survive.
Photosynthesis is a process that is used by plants, bacteria and certain types of algae. The process takes place in two phases: light reactions and dark reactions. Light reactions take place in the presence of light, and during this phase, sunlight is converted into chemical energy. During the dark reactions phase, the energy is then converted into sugar.