A U.S. tariff on steel would increase the domestic quantity of steel demanded.

The ratio of a country's exports to its total output (GNP or GDP)

A) is known as the index of openness. B) provides a rough measure of the importance of international trade to that economy. C) if calculated for the United States would be quite low. D) All of the above.

The perfectly competitive market structure results in economic efficiency because:

a. price is equal to marginal revenue in the short run. b. firms are producing at the minimum point of the average-total-cost curve in the short run. c. a normal profit is being earned in the long run. d. a normal profit is being earned in the short run. e. in the long-run, price is equal to marginal cost and minimum average-total-cost.