As a general rule, oligopoly exists when the four-firm concentration ratio:

Which of the following is the best example of a differentiated product?

A) beets in the local supermarket B) diamonds C) airlines D) running shoes E) electricity

Your text mentions several ways that international trade flows are qualitatively different than they were a century ago. Which of the following is NOT one of those ways?

A) Firms' investment spending on capital goods is more important than in the past. B) International trade in raw commodities and agricultural products is more important than it was in the past. C) It is possible to trade some types of services in a way that was not possible in the past. D) Multinational corporations play a bigger role in production than they did in the past.