Final answer:
Biodiversity refers to the variety of life and the number of different species in an environment. The most closely related term to the number of species in an environment is biodiversity, and biodiversity hotspots contain a large number of endemic species.
Step-by-step explanation:
The concept most closely related to the number of different species found in an environment is B. biodiversity. Biodiversity is a general term for the variety of life in a particular habitat or ecosystem. It includes not only the number of different species (species richness) but also their relative abundance. High biodiversity indicates a wide variety of species and serves as a key indicator of the health and sustainability of an ecosystem.
In a biodiversity hotspot, one would expect to find B. a large number of endemic species, which are species that are unique to that specific location and not found anywhere else in the world. These areas are extremely important for conservation efforts because they are rich in biodiversity but often under threat from human activities.