So that's an example of autotrophs. Autotrophs obtain their carbon source from inorganic materials, while out of heterotrophs need to obtain the organic carbon from other organisms. Now let's move on to our energy source. So, once again, let's use humans as our example. Humans are examples of chemotrophs because they basically obtain their energy source by breaking down macromolecules, such as sugars, lipids, and proteins. We basically store that energy in molecules known as ATP or adenosine triphosphate.