Final answer:
Species richness is the term used to describe the number of different species present in a community, which is a key measure of biodiversity. The correct answer is option C.
Step-by-step explanation:
The number of different species present in a community is known as species richness. This biological term is used to describe the count of species within a defined area, such as a habitat, a biome, or the entire biosphere. Species richness is a measure of biodiversity, which varies across different regions of the globe and is influenced by factors such as latitude, climate predictability, as well as ecological aspects like island size and proximity to the mainland in island biogeography.