Ecologists use food web diagrams, like the one shown, as tools in their studies of different populations of organisms within an ecosystem. Which of the following is a correct use for a food web diagram?

It is a way to show the living and nonliving components of a complete ecosystem in a form that is easy to understand.
It can change one population's role in the ecosystem and thereby change that population's relationship to the others.
It is a way to summarize and communicate the feeding relationships between populations.
It provides a basis for making predictions about how changes in the size of one population will affect the size of another.
It is a way to show an organism's role in the ecosystem (i. e., producer, primary consumer, secondary consumer).