Final answer:
Economies of scale are an advantage of a monopoly because they allow the monopolistic producer to serve the entire market more efficiently and at lower costs and prices.
Step-by-step explanation:
Economies of scale are an advantage of a monopoly because they allow the monopolistic producer to serve the entire market more efficiently than multiple smaller producers. In a natural monopoly, the marginal cost of adding an additional customer is very low once the fixed costs are in place.
This means that once the main infrastructure, such as water pipes or electrical lines, is laid, the cost of providing the service to an additional customer is minimal. It would be costly for a second producer to enter the market and duplicate the infrastructure. Therefore, the large economies of scale enjoyed by a monopoly allow it to offer services at lower costs and prices compared to competition.