Which of the following best describes an ecosystem?

An ecosystem is best described as a community of organisms interacting with their environment. This definition encapsulates the complex relationships between living organisms—such as plants, animals, and microorganisms—and their physical surroundings, including soil, water, and climate. In an ecosystem, different species coexist, contribute to biological diversity, and play various roles such as producers, consumers, and decomposers.

The interactions within an ecosystem, including food chains, nutrient cycles, and symbiotic relationships, are crucial for maintaining the balance and health of the environment. This interdependence highlights how organisms rely on one another and their surroundings for survival, reproduction, and overall ecosystem functionality.

Other options describe elements that do not comprehensively capture the essence of an ecosystem. For instance, a collection of human-made systems does not relate to natural interactions among organisms. A specific habitat for one species may describe an ecological niche, but it lacks the community aspect present in a true ecosystem. Lastly, an area defined merely by its chemical properties overlooks the biological components and interactions that are fundamental to the definition of an ecosystem.