Photosynthesis is the process by which plants convert sunlight into food, or energy(a.k.a. sugar). Most producers are plants that cannot "eat" food, so they have to make it themselves. They are usually called producers in a food chain and are at the bottom of most food chains.

Formula: CO2+H20=>CH2O+O2

The process of photosynthesis takes in carbon dioxide and water and sunlight. Then it processes it into glucose (or sugar) and what is left is dumped into the air (oxygen).