Answer
Studying identical twins raised in different environments can help delineate between genetically determined and learned or environmental patterns that can otherwise be difficult or impossible to determine.
Work Step by Step
In any kind of research on any kind of animal, it can be difficult to determine what internal and external factors are most contributory to the observed outcomes. Identical twins have the same genetic makeup, so observing the ways in which they are the same and different when raised in different environments can help determine where innate genetic factors are and are not in play.