Answer:
Separated by city states
Step-by-step explanation:
Mesopotamia as one of the oldest and most innovative cultural hearth, would have been better developed by city states, due to the variety of sources and jobs for people.
Since it was situated between the Tigris and Euphrates Rivers, according to where people were located, they would develop different roles.
Mesopotamia reached their best by being divided on Akkadians and Sumerians, on which each did their own. Later on when conquered by different emperors, Mesopotamia didn't progress much due to people overall having different needs and interests.