What term is used to describe the variety and variability of life forms in a given environment?

The term that accurately describes the variety and variability of life forms in a given environment is biodiversity. Biodiversity encompasses not only the number of different species present but also the genetic diversity within those species and the variety of ecosystems in which they exist. This concept highlights the complex relationships among organisms and their environments, emphasizing both the richness of species and their interactions.

In contrast, diversity can refer to a broader range of contexts and is not specific to biological systems. Population density indicates how many individuals of a species live in a particular area, but it does not capture the variety of life forms. Species richness focuses specifically on the number of different species in an area, without considering the genetic variations or ecosystem diversity that biodiversity includes. Thus, biodiversity is the most comprehensive and accurate term for describing the variety of life forms in any environment.