What is the unconditioned stimulus and the unconditioned response Sophia usually loves bananas, but last week she got really sick and vomited right after eating one. Now, just the sight or smell of a banana makes her
nauseous

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.