In a newspaper column, Frank Wolak, a professor of economics at Stanford, referred to "the economic forces that lead to most children's toys being developed in the United States and mass-produced in China and other developing countries." What economic forces is he referring to? If a U.S. company develops a toy, why is a Chinese company likely to end up manufacturing the toy? Source: Frank A. Wolak, "Our Comparative Advantage," New York Times, January 19, 2011.