Photosynthesis, (Pronunciation: foh tuh SIHN thuh sihs or foh toh SIHN thuh sihs) is a food-making process that occurs in green plants. Photosynthesis is the chief function of leaves. The word photosynthesis means putting together with light.

Green plants use energy from light to combine carbon dioxide and water to make food. All our food comes from this important energy-converting activity of green plants. Light energy is converted to chemical energy and is stored in the food that is made by green plants. Animals eat the plants, and we eat animal products as well as plants.