Hayley has a snake phobia. she has always avoided situations in which she may encounter a snake, and she will even avoid viewing pictures of them. if hayley’s therapist approaches her problem from a behavioral perspective, he may use:

The correct answer is - Exposure therapy.

Explanation:

In behavioral therapy, Exposure therapy is a technique used to treat a number of anxiety disorders and phobias. During the application of this technique, an individual is exposed to the anxiety or phobia source without putting him or her into an actual danger, with a goal of changing the response.  

Here, Hayley’s therapist may choose to show her pictures of snakes (exposure), which she would usually avoid. Furthermore, on the later stage therapist might encourage her to go and see alive snake in the zoo in order to increase the strength of stimulus. By presenting Hayley with the stimulus (snakes) therapist will work on breaking the pattern, which makes Hayley to experience fear.

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.