Why is photosynthesis so important to plants, and can't animals use it?

It gives them food and animals don't have the ability to produce the energy they need to live 

Photosynthesis is pretty much what plants eat.
They convert the sunlight into glucose( its like sugar for plants)
Animals can`t use it because they don`t have the same type of cells a plant has.

Most smaller stars don't have a radiative zone.

C: plants and animals