Which type of boundary would you most likely cause the greatest political problems?

Geographic boundaries that follow ethnic or cultural lines, often referred to as "ethnic boundaries," are most likely to cause significant political problems. These boundaries can lead to tensions and conflicts when different ethnic groups are separated or forced together, resulting in issues such as discrimination, civil unrest, or even violence. Additionally, the creation of such boundaries can lead to disputes over territory and resources, further exacerbating political instability. Examples include the borders in the Balkans or the division of communities in regions like the Middle East.