Answer:
Common language, common religion, and common customs, is the right answer.
Step-by-step explanation:
Ancient Greece was comprised of various city-states. A powerful city was at the center of every city-state. This city was responsible for the management in the nearby area. The city-states were known as the "polis". Though there were some differences between various city-states of Greece one example can be seen in the form of government these city-states followed. While the Athens followed the Direct Democratic form of government Sparta followed the Oligarchy form of government. However, the common language, common customs and common religion bound these city-states together.