Review Questions 5.1 What is intraindustry trade, how is it measured, and how does it differ from interindustry trade? Are the gains from trade similar? 5.2 A monopolistic competition, like the one shaping the United States' semiconductor industry, is often led by internal economies of scale. How does this relatively common market structure benefit consumers? 5.3 What are the differences between external and internal economies of scale with respect to the size of firms, market structure, and gains from trade?