In this scenario, the student is a passive participant in the process. The information learned is impersonal. Clearly, the teacher is in control of the learning process; his or her interests dictate what and how fast the students learn.
The answer in all three cases is that rudder is used to help maintain stability in the roll. A little rudder at just the right time can help keep the nose up in a slow roll or even an aileron roll, as the plane rotates through the sideways portions of the roll when gravity is otherwise not countered.
The anal fin on the underside of the shark serves the same purpose. It is often said that the anatomy of an airplane is very similar to that of a shark. When you visualize this in your mind you can see it is very true. There is a tail and the wings to help balance everything and to give it speed.