35. What is opportunity cost? How does the concept help to explain why industrial workers in the developing world are paid less than those in the developed world? 36. What is absolute advantage? What is comparative advantage? According to most economists, which is the more useful concept for thinking about which countries will export what? 37. Make sure that you can work out, using a basic 2-good, 2-country, 1-input, Ricardean framework, which country has a comparative advantage in the production of which good. Make sure you can demonstrate why they could gain from trading 38. Make sure that you can work out, using a basic 2-good, 2-country, 2-factor, Heckscher-Ohlin framework, which country has a comparative advantage in the production of which good; how demand for each factor of production would shift on opening up to trade; and what this would do the incomes of people who own the different factors of production in each country