Which level of organization encompasses both populations and communities?

The ecosystem level of organization incorporates both populations and communities because it represents a broader biological unit that includes living organisms (biotics) and their physical environment (abiotics). In this context, populations are groups of individuals of the same species that live in a specific area, while communities consist of different species interacting within that same area. An ecosystem thus encompasses all of these interactions, including how populations within a community relate to each other and to their physical surroundings.

A biome is a larger geographic area characterized by specific climate conditions and types of organisms, but it does not directly include the interactions associated with populations and communities. The population level focuses solely on individuals of the same species, and the organism level pertains to individual living entities. Hence, when considering the overarching structure that includes both populations and communities, the ecosystem is the appropriate classification.