8. the factor-price equalization theory and transportation costs which of the following statements about the factor-price equalization theory and the effects of transportation costs are correct? check all that apply. differences in transportation costs across countries are a source of comparative advantage. in trading nations, the cheap resource becomes even less expensive, and the expensive resource becomes even more expensive, which facilitates the growth of trade. the factor-endowment theory accounts for transportation costs and other trade barriers. when nations trade, the cheap resource becomes relatively more expensive, and the expensive resource becomes relatively less expensive, until price equalization occurs.