What distinguishes a natural monopoly from other monopolies? What are the pros and cons of regulating natural monopolies? Does your answer differ depending on the specific product or industry being regulated? What are the key differentiating characteristics of a market characterized by oligopoly versus monopolistic competition? Provide one specific example of each type of industry and defend your assignment of the industry to monopolistic competition or oligopoly. What makes the monopolistic competition model different from the monopoly model? Explain how the differences affect short- and long-run equilibrium.