What is the term used for the physical space used by a population?

The term used for the physical space occupied by a population is "habitat." A habitat refers specifically to the environment that provides the resources and conditions necessary for a particular species to survive and reproduce. It encompasses all the biotic (living) and abiotic (non-living) factors that organisms interact with. This can include everything from the vegetation and climate of an area to its water sources and shelter options.

In contrast, a biome refers to a larger ecological classification that includes multiple habitats sharing similar climate and geographical features, while an ecological niche describes the role and position a species has within its environment, including its interactions with other organisms and its role in energy flow and nutrient cycling. Population density, on the other hand, quantifies how many individuals of a species live in a given area but does not specify the physical environment those individuals inhabit. Thus, habitat is the most accurate term to describe the physical space used by a population.