What is biodiversity?

Biodiversity is defined as the variety of life in a particular habitat or ecosystem. This encompasses not only the different species of plants, animals, and microorganisms but also the genetic diversity within those species and the variety of ecosystems themselves. It is a crucial measure of the health and stability of an environment, as higher biodiversity often contributes to greater resilience against environmental changes and disturbances. Biodiversity ensures that ecosystems can function effectively, supporting processes such as pollination, nutrient cycling, and climate regulation, all of which are vital for sustaining life on Earth.

The other options focus on specific aspects that do not fully capture the breadth of biodiversity. For example, the total number of organisms in a habitat and the density of animals refer more to population metrics rather than the diversity of life forms. The average size of species in a region is also a limited perspective, as it does not address the variety or richness of different species present in ecosystems. Therefore, while these aspects are related to ecological studies, they do not encompass the complete definition of biodiversity.