Which of the following makes the United States the strongest of the world's three economic centers? Multiple Choice The American working population is more hard-working and intelligent than workers anywhere else in the world. Its trade surplus is easily the world's largest. The United States ranks among the top five nations in the extraction of gold. The United States ranks among the top three countries worldwide in the production of manufactured consumer goods. Its vast, fertile plains and advanced farming methods have made it the world's leading agricultural producer