Which of these statements are barriers to North Korean citizens being able to freely elect their leaders? I. North Korea effectively only has one political party.
II. North Korea's president greatly influences who runs in each election.
III. North Korean citizens are not allowed to vote.

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.