An autotroph is an organism that can produce its own food. An example would be plants because they use sunlight, air, and water to make their own food which is the process defined as photosynthesis. This is the process where plants soak up the water through the roots. Also, some bacteria produce their own food to live as well. It's important to understand that photosynthesis is not the only way that organisms can produce their own food. They can also produce their own food by something called chemosynthesis.