Final answer:
The primary purpose of advertisements is to differentiate products and increase a firm's profits.
Step-by-step explanation:
The primary purpose of advertisements is to explain to people and make them believe that the products of one firm are differentiated from another firm's products. In the framework of monopolistic competition, advertising can cause a firm's perceived demand curve to become more inelastic or increase demand for the firm's product. A successful advertising campaign can allow a firm to sell a greater quantity, charge a higher price, or both, and increase its profits.