Answer:
Correct answer is government.
Step-by-step explanation:
Government is the correct answer as the civilizations created first form of government and political system so they can govern themselves and improve.
Cities is not correct as besides cities people were and are living in different types of settlements.
Religion is not correct as different beliefs are not the main reason for development of civilization.
Writing is also important, as the people were able to express themselves, but is not the main factor of development of civilizations.