Photosynthesis is a process that allows plants and some other organisms to use light energy to make their own food. In this process, water and carbon dioxide are converted into oxygen and sugar, which can be used for energy and growth. Photosynthesis is essential for life on Earth, as it provides oxygen for animals and humans, and stores solar energy in organic molecules. Photosynthesis also helps regulate the amount of carbon dioxide in the atmosphere, which affects the climate. Photosynthesis occurs in two main stages: the light-dependent reactions and the light-independent reactions. The light-dependent reactions capture light energy and use it to make ATP and NADPH, which are molecules that store energy. The light-independent reactions use these molecules to make sugar from carbon dioxide. Photosynthesis takes place in special structures called chloroplasts, which contain a green pigment called chlorophyll. Chlorophyll absorbs blue and red light, and reflects green light, giving plants their green color.