Which could be a pathway of food through an ecosystem?

Food energy can pass from an autotroph, such as a plant, to a heterotroph that eats it, and then to another heterotroph that eats the first consumer. Thus, “autotroph → heterotroph → heterotroph” is a possible pathway. The other choices place an autotroph after a consumer, or have one autotroph feeding on another, which is not the usual food-energy pathway in an ecosystem.

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