The U.S. economy relies heavily on international trade. Choose two transactions at random that result from international trade; one where purchases are made from another country and one where the U.S. sends a product to another country. Identify the impact of each of these on imports, exports, net imports, and net exports at the time the transaction takes place.    

For example, if you purchase a product online that is made in and shipped from Italy to you in the United States what is the effect on the U.S. economy in these four categories at the time of the transaction?   

In addition, there has been a lot of news in recent years surrounding tariffs. Exactly what is a tariff and what is the impact of tariffs on international trade? Who pays the cost of tarffs?  

Please present your explanation in a well-written narrative complete with an introduction to global trade, good paragraph structure, and footnotes. Do not list bullet points.