Which definition best describes an ecosystem?

An ecosystem is best described as a community of organisms interacting with their environment. This definition captures the essence of an ecosystem, which includes both living (biotic) components, such as plants, animals, and microorganisms, and non-living (abiotic) components, such as water, soil, and climate. In an ecosystem, these organisms interact with one another and with their surroundings in multiple ways, such as through food chains, nutrient cycles, and energy flows. This interaction emphasizes the interconnectedness of life and the importance of environmental conditions in shaping the processes and relationships within the ecosystem.

The other choices provide narrower or incomplete perspectives that do not encompass the full scope of what an ecosystem represents. While a group of organisms of the same species refers to a population, it lacks the critical interaction with the broader environmental context. Chemical processes are indeed vital to life, but they represent only a part of the functioning of ecosystems rather than the whole. Finally, an area defined by specific climatic conditions does describe an ecological zone, but it does not encompass the interactions among organisms that define an ecosystem. Therefore, the first definition is the most inclusive and accurate representation of an ecosystem.