Question

this makes heterotrophs a consumer, as they must consume others for energy and matter. energy always flows from a producer, such as a green plant, to a consumer, such as a deer. what is best defined as an organism that \must consume another living thing to maintain its energy?\ producer autotroph heterotroph

Explanation:

A heterotroph consumes other organisms for energy. Producers (like plants) make their own energy. Autotrophs (similar to producers) also produce energy. The question's description matches heterotroph.

Answer:

heterotroph