What is the definition of biological diversity?

Biological diversity, often referred to as biodiversity, encompasses the total variety of life on Earth. This includes the number and variety of species, as well as the genetic differences within those species and the ecosystems in which they live. The correct definition emphasizes the number and variety of organisms in an area, as it reflects the comprehensive nature of biodiversity beyond just species count.

This definition captures the essence of biological diversity, as it addresses the sheer volume of living organisms—ranging from microorganisms to larger plants and animals—while also acknowledging the intricate relationships and interactions that occur within different ecosystems. By including both the organisms present and their variety, it provides a broader understanding of how biodiversity is measured and appreciated within specific geographical regions.

Other options, while they touch on important aspects of biodiversity, focus more narrowly on specific components such as species count, habitat range, or genetic variation within a single species, which are all essential facets of the broader concept of biodiversity as defined in the chosen answer.