Photosynthesis is the most important biological process on Earth. It acts like World's largest solar battery. Photosynthesis converts amount of Sunlight into electrical and then chemical energy. Photosynthesis fills all of our food requirements directly or indirectly. Plant kingdom, either directly or through herbivorous animals meets all of our biological energy needs. The energy present in petroleum, natural gas and coal come from sun through photosynthesis. Also the energy in firewood, which is a major fuel in many parts of the world comes from photosynthesis. It fixes carbon dioxide and releases oxygen, thereby reducing the green house effect and global warming.