Autotrophs are the base of most food chains and ecosystems. They make their own food through processes like photosynthesis (using sunlight) or chemosynthesis (using chemicals).

Examples of autotrophs include:

* Plants: They use photosynthesis to convert sunlight, water, and carbon dioxide into glucose (sugar).

* Algae: Like plants, they also use photosynthesis.

* Some bacteria: They use chemosynthesis, which uses chemicals like hydrogen sulfide to produce energy.