In social studies with one question

Historians believe that Christianity played a role in ending the Roman Empire because it changed the relationship between the citizens and their government as well as created power struggles between other important religious leaders and the government. With the spread of Christianity citizens focused more on their God and became less fearful and subservient to the state which no longer was backed by the Roman gods. Also new powerful religious figures challenged the state for legitimacy and created power struggles within the empire. 

An informal structure in a bureaucracy would be something like so-called "office politics". where there's a formal structure set up for the organization, but then an informal subculture as well that has a way of organizing the bureaucracy further. this can be positive because it sets up an added degree of organization, albeit informal, within the bureaucracy.