How does trade influence the strength of the economy worldwide?

Analyze measures of economic growth, and comparative and absolute advantage in international trade for the following countries:
USA
China
Saudi Arabia
Democratic Republic of Congo
Research each country, using such resources as the CIA World Fact Book, World Bank data, and World Trade Organization. Research its economic, political, and cultural development.
Compare the following using tables or graphs, for most recent year available and for 2009 (the trough of the last economic cycle):
Country GDP per Capita
Country GDP as a % of World GDP
Country exports per capita
Country exports as a % of GDP
Country exports as a % of World exports.
Country imports per capita
Country imports as a % of GDP
Country imports as a % of World imports (world imports = world exports)
Discuss reasons why the economic growth of the four countries varies so markedly. How does trade influence the strength of the economy worldwide?
Determine the stage in the lifecycle for each country’s economy.
Discuss the following for each country:
At least two products that have provided the country an absolute advantage in trade (if any)
At least two products that have provided the country a comparative advantage in trade
Factors that have prevented a country from achieving either
I selected United States.