This migration was primarily driven by A political push factors. B economic pull factors. C environmental push factors. D social pull factors.

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.

answer; traditional culture;

answer; make a no-nonsense accusation of the other;