Answer:
I believe the answer is city-state structure.
I hope I helped, please correct me if I'm wrong!
Three factors fueled American Imperialism.
Economic competition among industrial nations. Political and military competition, including the creation of a strong naval force. A belief in the racial and cultural superiority of people of Anglo-Saxon descent.
The Ancient Greek civilization is so well known because of how much it impacts society today. They were the first ones to set the stage to many key things still used today like philosophy, literature, astronomy, mathematics, and medicine. Not only does it impact us it also affected other great civilizations like the Roman Empire. They overall are the root of who we are as a society today especially in the education aspect.