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. Now, the other type of molecule, the other type of organism that basically uses light as the energy source are known as phototrophs. So basically, plants are example of phototrophs because they use the energy stored and light to basically synthesize carbohydrate molecules. So they combine carbon dioxide, our inorganic carbon source, with water, and by using our light, they synthesize our carbohydrates as well as oxygen.