Of the rivers that supplied its water has been The Aral Sea has almost completely dried up because the
changed.
A. number
B. source
C. quality
D. direction

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.