Which biodiversity metric simply counts the number of species in an area?

• A. Biomass
• B. Species richness
• C. Evenness
• D. Species abundance

Answer: (B)

The main idea is a simple tally of how many different species are present in an area. That tally is called species richness because it counts each species once, regardless of how many individuals there are of each species or how those individuals are distributed.

Other metrics measure different things: biomass sums up the total mass of all organisms in the area, giving a sense of overall biomass rather than variety; evenness looks at how evenly individuals are spread across species, not how many species exist; and species abundance tracks how many individuals belong to each species. So, when the question asks for a metric that simply counts the number of species, species richness is the best fit.