What is an ecosystem?

An ecosystem is defined as a combination of living organisms and their physical environment. This includes not only the various species that inhabit the area, such as plants, animals, fungi, and microorganisms, but also the non-living components like water, air, soil, and climate that influence these organisms. The interaction between these biotic (living) and abiotic (non-living) factors creates a dynamic system in which energy and nutrients cycle, supporting life and influencing the overall health and functioning of the ecosystem.

The other options focus on only one aspect of an ecosystem. For instance, a collection of non-living factors or a system of abiotic factors ignores the living organisms that are crucial for the functioning of an ecosystem. Furthermore, a group of organisms of the same species pertains specifically to a population, which is just one part of the larger ecosystem framework and does not encompass the interactions with their physical environment. Thus, the correct answer captures the comprehensive nature of ecosystems as inclusive of both living and non-living components and their interactions.