The city-states were autonomous and independent cities that had their own political regime.
This form of governing arose in the 8th century BC. The structure was much used in antiquity, where most of the cities had their own monarch, language and even religion.
An example was Athens, which was an autonomous city-state (or polis) of Ancient Greece.
The correct answer is government. Here in the United States, to fill the purpose of government we have things such as the Navy, Air Force and other military branches.
