The organisms that use energy to make their own food by the process of photosynthesis are called photoautotrophs.

Here are some examples of photoautotrophs:

* Plants: The most common example.

* Algae: These can be single-celled or multicellular and are found in freshwater, saltwater, and even on land.

* Cyanobacteria: These are photosynthetic bacteria that can be found in various environments.

These organisms use sunlight, water, and carbon dioxide to create glucose (a type of sugar) and oxygen. This process is essential for life on Earth as it provides the basis for most food chains.