The book shows a business organization chart in figure 2.5a (it's also in the Concepts and Architecture slide set.) Assume this is a fairly large company with more than three people in the Information Technology division. If you were asked to draw a detailed organization chart for IT, it would likely have many more boxes, including managers and employees for each department within IT. What abstraction mechanism is "zooming in" on a particular area called? (One word is enough.)

Both the organization chart of figure 2.5a and the more detailed chart described above are abstractions of the organization of the company. Give an example of a case where the figure in the book would be more useful. Also give an example where the more detailed chart would be more useful.