(Figure: Cell Phones and Automobiles) Use Figure: Cell Phones and Automobiles. The movement from production possibility frontier 1 (PPF1) to production possibility frontier 2 (PPF2) indicates: A graph plots Cell phones on the vertical axis versus Automobiles on the horizontal axis and shows two parallel concave down decreasing curves. Both curves start on the vertical axis and end on the horizontal axis. The lower curve is labeled, ?P P F subscript 1? and the upper curve is labeled, ?P P F subscript 2.? Two points, X and Y, are marked on the lower curve, from top to bottom. A point Z is marked above the upper curve, to the right point X