Photosynthesis. Plants use the carbon dioxide that we breathe out and mix it with water to create nutrients that they need to survive. A byproduct of this is oxygen.
Photosynthesis and chemosynthesis are both processes by which organisms produce food; photosynthesis is powered by sunlight while chemosynthesis runs on chemical energy. ... Ecosystems depend upon the ability of some organisms to convert inorganic compounds into food that other organisms can then exploit (or eat!).
