When casey opens her eyes in the morning she sees a photograph by her bedside. at that point, her eyes are receiving light energy. her eyes then change the light energy into neural messages for the brain to process. this conversion of one form of energy into another is called:

they all focused on themes about the inevitability of death.

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.