A hybrid zone is properly defined as
A) an area where two closely related species' ranges overlap.
B) an area where mating occurs between members of two closely related species, producing viable offspring.
C) a zone that features a gradual change in species composition where two neighboring ecosystems border each other.
D) a zone that includes the intermediate portion of a cline.
E) an area where members of two closely related species intermingle, but experience no gene flow.
Answer: B