Which of the following is not a characteristic of a civilization?

There are six: 

1) Geographic Boundaries and political insitutuionsPermanent boundryA government to rule within the boundaries

2) Population (a concentration) in distinct areas or citiesGroup of people in a place to trade with

3) Economy that produces food surplusestrade extra food to survive and stay in one place

4) Social classestheese are based on POWER, such as upper, lower and middle classes

5) Written language/a system of recordkeepingRecording trade and/or buisnessRecording historyCommunicating (spoken or written communication)

6) cultural systems:Religion: at least one organized religion in a civilizationLearing: formal system of education such as apprenticeship or schooling systemsArt: You have extra time to do this- meaning you know you'll survive tommorowArchitecture: planning your building/ thinking about the structure and going through many steps to build it to last long term.