What defines a consumer in an ecosystem?

A consumer in an ecosystem is defined as an organism that consumes other organisms for energy. This can include herbivores, which eat plants, and carnivores or omnivores, which consume other animals or a mix of both. Consumers play a vital role in the food chain as they transfer energy from producers (organisms that perform photosynthesis, such as plants) to higher trophic levels, while also helping to regulate populations of other species.

The other choices describe different types of organisms or functions within an ecosystem. Organisms that perform photosynthesis or produce energy from the sun are producers, not consumers. Recycling nutrients typically refers to decomposers, which break down dead organic matter and release nutrients back into the environment. Thus, the role of a consumer specifically pertains to those organisms that rely on others for their energy needs.