Concept:The terms autotrophs, heterotrophs, and decomposers describe the feeding roles of living organisms. These roles together form the biotic community of a natural system.
Explanation:Autotrophs are producers, such as green plants, that prepare their own food using sunlight or chemical energy.
Heterotrophs are consumers, like animals, which obtain food by eating other living things.
Decomposers, such as fungi and bacteria, break down dead bodies and organic wastes into simpler substances.
All three groups interact with one another and with the non-living surroundings.
This interaction of living organisms and their physical environment is known as an ecosystem.
Vegetation, climate, and geology are only parts or conditions of this larger system, not the association of these three feeding groups.
Therefore, autotrophs, heterotrophs, and decomposers are all related to an ecosystem.
Answer:C. Ecosystem