Photosynthesis is the process by which plants use carbon dioxide, water and sunlight to produce their own food in the form of sugars. Chlorophyll in plants traps energy from sunlight to power the production of glucose from carbon dioxide and water, with oxygen released as a byproduct. This process is essential to human life as it provides the oxygen we breathe out and uses the carbon dioxide we breathe out, establishing an interdependent relationship where plants produce food and oxygen for humans.