1. which of the following statements best supports all three species concepts?
a. biological diversity does not vary in a smooth, incremental way.
b. in some cases, it may be difficult to predict whether incipient species will continue to diverge.
c. virtually all species exhibit some degree of genetic recombination among individuals.
d. hybrid zones may form if reproductive isolation is incomplete.
e. a single lineage may evolve over time without giving rise to a new species.