What term is used for a living thing that obtains energy from eating plants or animals?

The term that refers to a living thing that obtains energy from eating plants or animals is "consumer." Consumers are organisms that cannot produce their own food and must rely on other living things for energy. They play a crucial role in the food chain by transferring energy from producers (like plants) and other consumers to themselves.

In ecology, consumers are typically categorized into various groups based on their diets: herbivores (which eat plants), carnivores (which eat other animals), and omnivores (which consume both plants and animals). This diversity among consumers highlights their role in maintaining the balance of ecosystems by regulating the populations of producers and other consumers.

The other options, such as producers and decomposers, refer to different ecological roles. Producers create their own energy through photosynthesis, while decomposers break down organic matter, returning nutrients to the ecosystem. Herbivores are a specific type of consumer, but the term "consumer" encompasses all organisms that obtain energy through eating.