What is often at the bottom of food chain?

Plants are usually at the bottom of the food chain. The thing at the bottom of the food chain has to be able to make its own food, if it ate anything it would no longer be at the bottom of the food chain. Plants make their own food from carbon dioxide, water and sunlight in a process called photosynthesis.

i agree and would just like to add the sun isn't the bottem of the food chain