Answer the following question given this paragraph: 

A food chain is a simple diagram that shows one way energy flows through an ecosystem. Pictured below is an example of a food chain ( Figure below ). Producers form the base of all food chains. The consumers that eat producers are called primary consumers. The consumers that eat primary consumers are secondary consumers. This chain can continue to multiple levels.


Q: What is a diagram that shows a single way that energy flows throughout an ecosystem?

 Choices:

- fuel chain

- dependent chain

- water cycle

- food chain

A:
food chain
