Answer:
In most of other region people were still living in tribal communities and didn't have developed organization and social structure. The only exception is Egypt, because in the valley of Nile during the 3rd Millennium BC new civilization appeared.
Step-by-step explanation:
Sumerian city-states are the cradle of civilization. They created first political system that was functional. Still, they were surrounded by many tribes, that later tried to conquer them. Of course, they weren't on the same level of development. The exception is Egypt, where with the unification Lower and Upper part another ancient civilization and state was created.