Volpe's Understanding Evolution 7th Edition by Peter Rosenbaum

Exercise 8

In eastern North America, two species of gray treefrogs exist that are phenotypically indistinguishable. How do they tell the differences between each other in nature?
A) By smell
B) By mating call
C) By habitat isolation (living in different habitats)
D) By seasonal isolation (mating at different times of the year)
E) By spontaneous generation