Explanation:
The main purpose of photosynthesis is to convert radiant energy from the sun into chemical energy that can be used for food. Cellular respiration is the process that occurs in the mitochondria of organisms (animals and plants) to break down sugar in the presence of oxygen to release energy in the form of ATP.
♣Combustion. (Science: chemistry) The heat-producing reaction of a material with oxygen gas or other oxidant, often producing a flame.
♣Substances or materials which undergo combustion are called fuels. The most common examples are natural gas, propane, kerosene, diesel, petrol, charcoal, coal, wood, etc.
♣Geological processes are events that occur on a geological timescale ranging between millions of centuries, hundreds of meters and thousands of kilometers.
