A constant contributor to labor productivity growth during the entire 1948–2000 period was

If foreigners spend more on U.S.-made goods and services than we spend on theirs

A) foreigners must borrow from the United States or sell U.S. assets to make up the difference. B) all U.S. national saving remains in the United States. C) we must borrow from foreigners because of low imports. D) funds flow in from abroad to help finance U.S. investment.

When two countries trade with one another, it is most likely because

a. the wealthy people in each of the two countries are able to benefit, through trade, by taking advantage of other people who are poor. b. some people involved in the trade do not understand that one of the two countries will become worse-off because of the trade. c. the opportunity costs of producing various goods are identical for the two countries. d. the two countries wish to take advantage of the principle of comparative advantage.