Using one diagram to represent the situation of the representative firm in the perfectly competitive industry and one diagram to represent the overall market situation of the industry, explain the short-run and long-run impact on price and output of a decrease in demand. Assume that initially the market is in equilibrium with the representative firm earning zero economic profit. Show the case of a constant-cost industry. In the diagram of the overall market situation of the industry, label the initial equilibrium as A, the new short-run equilibrium as B, and the final long-run equilibrium as C. Be sure to mention the role of economic loss in the process by which long-run equilibrium is reached