The process that plants carry out in the presence of radiant energy in order to create their food is known as photosynthesis. This process is one of the reasons because of which man and other forms of life are alive on the Earth today. This process basically occurs in the green parts of leaves. This process requires Water, Soil, Sunlight, Carbon dioxide, Chlorophyll

The process begins with three most important non-living elements: water, soil, and carbon dioxide. Plants begin making their 'food', which basically includes large quantities of sugars and carbohydrate, when sunlight falls on their leaves. The 'food' is then stored aside by the plant and some of it is consumed during the day. This process goes on till the end of the day (until sunlight is available). The 'food' that is prepared by the plants is always in excess and humans and other animals consume it through different sources such as fruits and vegetables. Animals and human beings in return breathe out carbon dioxide during the process of cellular respiration. This carbon dioxide is in turn used by the plants to make more food. The rains and accumulated water table provides water to the plants and the sun provides light (radiant energy) every day. This process is thus, nothing but a cycle that goes on and on. According to the facts of this phenomenon, this cycle has been going on for almost 3,500 million years, which is quite a long time.