Final answer:
Option (C), Species diversity is the term used to describe diversity based on the number and relative abundances of species within a habitat or region.
Step-by-step explanation:
The term that specifies diversity based on the number of relative abundances of species in a habitat or any specified region is C) Species diversity. This measure of biodiversity takes into account not only the presence of various species within an ecosystem but also how those species are distributed in terms of their relative numbers.
A habitat with a balanced distribution of species exhibits greater species diversity as compared to one where few species predominate. Other forms of biodiversity include genetic diversity, which refers to the variety of genes within a population, and ecosystem diversity, which looks at the number of different ecosystems in a given area.