Photosynthesis is a process used by plants and other organisms to convert light energy, normally from the Sun, into chemical energy that can be later released to fuel the organisms' activities. Plants take the CO2 and water along with sunlight and produce O2 and energy which is stored in the form of sugar in the plants.
Green plants create carbohydrates on their own through the process of photosynthesis. These carbohydrates are the plant's source of fuel for growth. If even one basic ingredient a plant needs for photosynthesis is absent or lacking, the plant's health can suffer, resulting in stunted growth or reduced production.