Why were sumerian communities were called city-states?

Each of the cities were a separate political unit. As also with the ancient Greek cities states like Athens, Sparta, Corinth, etc. and the Italian cities during the Renaissance like Florence, Venice, etc. The city owned the land around it. People owed their allegiance to their individual cities. Even today in the time of national states, we still use words like politics, political, politician which stem from the word "polis" meaning city.

congress also has implied powers, which derive from the necessary and proper clause of the constitution and permit congress "to make all laws which shall be necessary and proper for carrying into execution the foregoing powers, and all other powers vested by this constitution in the government of the united states.

geography

this is because warmer climates often don't get people sick from the flu and regions where it was often colder more people received the flu. hope this if you need more reasoning i am here to