Which of the following statements about species, as defined by the biological species concept, is (are) correct?
I. Biological species are defined by reproductive isolation.
II. Biological species are the model used for grouping extinct forms of life.
III. All members of a species can potentially interbreed.
A) I and II
B) I and III
C) II and III
D) I, II, and III

Question

Quizplus · Accepted Answer

Statement I is correct because the biological species concept defines species as populations or groups of organisms that are reproductively isolated from one another, meaning that they cannot interbreed or produce viable offspring. 
Statement II is false because the biological species concept is only applicable to extant, living organisms, not extinct forms of life. 
Statement III is partially correct because all members of a species should be able to interbreed, but not necessarily with each other. There can be geographic or other barriers that prevent certain members of a species from interbreeding with others.

Which of the Following Statements About Species, as Defined by the Biological