Final answer:
Price fixing and supplier discrimination often signal monopoly power, which occurs in markets where a single firm can control prices due to lack of competition, contrasting with perfect competition where firms have no market power.
Step-by-step explanation:
Price fixing and supplier discrimination sometimes signal monopoly power. In a market with perfect competition, firms have no market power and cannot control prices or output levels because they are price takers in response to the market price. However, a monopoly exists when there is no competition at all, allowing the single firm to exercise a great deal of market power by determining prices and output without significant constraints from competitors. In the context of a natural monopoly, where a market runs most efficiently with one firm providing all of the output and barriers prevent other firms from entering, like with public water services, the government may step in to regulate prices to protect consumer interests. This dynamic illustrates that monopolies can manipulate prices due to their exclusive control over a commodity or service in the market.