Ans.1) Photosynthesis is a process that converts carbon dioxide into organic compounds, especially sugars, using the energy from sunlight.
Photosynthesis occurs in plants, algae, and many species of Bacteria, but not in Archaea. Photosynthetic organisms are called
photoautotrophs, since they can create their own food. In plants, algae and cyanobacteria photosynthesis uses
carbon dioxide and
water, releasing
oxygen as a waste product.
Photosynthesis is vital for life on Earth. As well as maintaining the normal level of
oxygen in the atmosphere, nearly all life either depends on it directly as a source of energy, or indirectly as the ultimate source of the energy in their food . The amount of energy trapped by
photosynthesis is immense, approximately 100 terawatts which is about six times larger than the power consumption of human civilization. As well as energy, photosynthesis is also the source of the carbon in all the organic compounds within organisms' bodies.