What defines an ecosystem?

The definition of an ecosystem encompasses both the living organisms—such as plants, animals, and microorganisms—and their physical environment, which includes elements like air, water, soil, and climate. This interconnected system highlights how organisms interact with each other and with their surroundings, emphasizing the flow of energy and the cycling of nutrients within that environment.

In contrast, while a collection of similar species refers to a population or community, it does not include the non-living components that are crucial to forming an ecosystem. Similarly, a food web illustrates the feeding relationships among organisms but does not encapsulate the entire concept of an ecosystem, as it focuses mainly on the biological interactions. Lastly, a specific geographical location does not inherently define an ecosystem unless it also considers the organisms and environmental factors present within that area. Thus, the comprehensive nature of the first option is what makes it the most accurate definition of an ecosystem.