Answer:
Photosynthesis happens in green plants and certain other organisms, they use the energy of light to convert carbon dioxide and water into the simple sugar glucose. by doing that, photosynthesis provides the basic energy source for basically all organisms. An important byproduct of photosynthesis is oxygen, on which most organisms depend.
Explanation:
basically they use it like we use food and oxygen, it gives them energy and acts as "food" for them by converting it to oxygen which they need :)