Which two frog species are most likely to interbreed?

The selection of peeper and leopard frogs as the most likely to interbreed is based on the compatibility of their genetic and reproductive characteristics. Both the peeper (Pseudacris crucifer) and the leopard frog (Lithobates pipiens) belong to the same family, Ranidae, and occupy similar ecological niches, which increases the likelihood of encountering one another during breeding season.

When two species are closely related and share a common habitat, they are more likely to mate and produce viable offspring. This is particularly true for species within the same genus or closely related genera, as they often have similar mating calls, behaviors, and physical traits. In this case, the peeper and leopard frogs have overlapping ranges and similar reproductive behaviors, which enhances the chance of hybridization.

In contrast, the other options involve species that may be more distantly related or have distinct differences in breeding behaviors, leading to a lower likelihood of successful interbreeding.