The Questions Below Are Based on the Following Description

Multiple Choice

The questions below are based on the following description.
Several closely related frog species of the genus Rana are found in the forests of the southeastern United States. The species boundaries are maintained by reproductive barriers. In each case, match the various descriptions of frogs below with the appropriate reproductive barrier listed.
-Males of one species sing only when its predators are absent; males of another species sing only when its predators are present.

A) behavioral
B) gametic
C) habitat
D) temporal
E) mechanical