"Comparative advantage can explain why people pursue different occupations. It can also explain why countries produce different goods and services. International trade involves many countries importing and exporting many different goods and services. Countries are better off if they specialize in producing the goods for which they have a comparative advantage. They can then trade for the goods for which other countries have a comparative advantage". Based on your knowledge of comparative advantage, look at U.S. exports and imports. Note that we both export and import some of the same products. If specialization is the essence of comparative advantage, why would we import and export the same product categories?