Why was ancient greek divided with a collection of city states?

Ancient Greece was divided into a collection of city-states (or Polis) because the population centers were isolated by the many islands, peninsulas and mountains that Ancient Greece had. Because of its geography, it made more sense for each Poli to have a government on their own.

i do not believe this was true indefiantly the native americans would have lsot aganist america one they didndt have the resources and allies that america had and 2   indians werent as advanced at the time as they were not 3 americans had the expreince because some of the soliders from other wars fought in that war and were attecked etc

the western roman empire flourished, but the eastern portion of the empire struggled.