Final answer:
Options (a), (b), and (c) under the biological species concept are correct, indicating that a species is a group of interbreeding populations isolated from others, are evolutionary independent, and do not typically exchange genes.
Step-by-step explanation:
Statement 1) A species represents a group of interbreeding (or potentially interbreeding) populations that are reproductively isolated from other such groups. This statement aligns with the fundamental principle of the biological species concept, emphasizing reproductive isolation as a criterion for defining a species. Reproductive isolation prevents gene flow between populations, promoting genetic distinctiveness.
Statement 2) Species are evolutionary independent units. This statement supports the idea that species, by being reproductively isolated, form distinct evolutionary lineages. The genetic divergence resulting from reproductive isolation contributes to the independent evolutionary trajectories of different species.
Statement 3) Different species do not exchange genes. The biological species concept implies that species maintain reproductive barriers that prevent gene flow between them. While some limited gene flow might occur in certain situations, the concept primarily emphasizes the restriction of gene exchange between distinct species due to reproductive isolation mechanisms.
Therefore, the biological species concept emphasizes reproductive isolation, evolutionary independence, and limited gene exchange between distinct species, aligning with statements 1, 2, and 3. Hence, option 5) a, b, and c are correct.