Final answer:
Autotrophs are the organisms that perform photosynthesis and form the first level of a food chain.
Step-by-step explanation:
The organisms that perform photosynthesis and form the first level of a food chain are called autotrophs. Autotrophs are able to produce their own food using energy from the sun, carbon dioxide, and water. They are also known as producers because they produce food for themselves and other organisms in the ecosystem.
Learn more about Autotrophs and photosynthesis