Detailed Instructions: Given scientific fact as input, generate the question from this fact such that it can be answered from the input.
Problem:Organisms categorized by ring species species descriptor demonstrate a version of allopatric speciation and have limited regions of overlap with one another, but where they overlap they interbreed successfully.
Solution:
Organisms categorized by what species descriptor demonstrate a version of allopatric speciation and have limited regions of overlap with one another, but where they overlap they interbreed successfully?