During the debate on the North American Free Trade Agreement (NAFTA), The Economist (September 11, 1993, p. 22) noted that average wages and fringe benefits in Mexican manufacturing industries were about one-fifth those in U.S. manufacturing and that U.S. output per worker was about five times that of Mexican manufacturing. Based on your understanding of this chapter and of the Classical model, is there any causal relationship between these two facts? Explain.