You carefully study populations of two very similar meadow mice, one from the northeast U. S. and one from southeast US. You want to know whether the populations belong to the same species or to two different species. Based on the Biological Species Concept you could most confidently decide this if you could:.

Explanation:

Based on the scenario being described within the question it can be said that  this can be confidently decided if you could show that the ranges of two mice overlap without hybridization occurring. This would allow you to safely predict  whether or not two species of mice have mated with one another or if it two populations are one in the same.