What is Mesopotamia/Sumer social structure?

Explanation:

The populations of these cities were divided into social classes which, like societies in every civilization throughout history, were hierarchical.

Explanation:

In Ancient Sumer, the social structure was very important. There were three different classes; the upper class, the common class, and the bottom. In the upper class, there were the priests, landowners, and government officials. They lived in the middle, or center of the city.

the answer is b. apsidal precession