Autotrophs are organisms that are capable of synthesizing their food through the process of photosynthesis.
In this process, autotrophs utilize carbon from simple organic compounds (such as carbon dioxide) and water to synthesize simple carbohydrates (such as glucose) in the presence of chlorophyll and sunlight.
Autotrophs release oxygen as a byproduct of photosynthesis.
Examples of autotrophs:
Examples of some autotrophs besides green plants are cyanobacteria (blue-green algae), green algae and red algae.