Which of the following best describes biodiversity? 

A)  speciation plus extinction 
B)  speciation minus coevolution 
C)  speciation minus extinction 
D)  speciation plus coevolution

Biodiversity is best described as the variety of life in the world or in a particular habitat or ecosystem. It is often considered in terms of the number of species, the genetic diversity among these species, and the variety of ecosystems they inhabit. The concept of biodiversity encompasses the balance of species being added through speciation and being lost through extinction. Therefore, biodiversity can be thought of as "speciation minus extinction," where the focus is on the net gain or loss of species over time.