See p. 600. Explain your answer. Wabash is a monopoly. Wabash is not a monopoly, since there are good substitutes for its product. It is a firm in a monopolistically competitive market.
Many firms sell college education.
These products are differentiated, but they are close substitutes. Even if it were a monopoly, Wabash would not necessarily be able to increase its revenues by increasing the price it charges. The Law of Diminishing Returns implies that, as world population grows, the marginal product of labor must fall. Therefore, increasing population must result in decreasing income per capita. This is an accurate application of the Law of Diminishing Returns.