Photosynthesis is a process used by most plants, algae, and some bacteria to convert light energy, water and carbon dioxide into chemical energy, in the form of sugars and starches, and oxygen. This process is made possible by special pigments that absorb light energy, mainly chlorophyll, which absorbs red and blue light and reflects green light.
Photosynthesis supplies most of the energy necessary for almost all forms of life and plays a key role in producing and maintaining the oxygen content of the atmosphere.