Measured between two points on a curve, the ratio of the change in the variable on the vertical axis to the change in the variable on the horizontal axis is the:

Which of the following statements about U.S. international trade in 2013 is CORRECT?

A) The value of U.S. exports exceeded the value of U.S. imports. B) The value of U.S. exports was about 33 percent of the value of total U.S. production. C) The United States imported only goods. D) The United States was the world's largest trader.

The lower portion of the circular flow model contains factor markets in which households provide:

a. output of all final goods and services produced. b. savings, spending, and investment. c. labor, money, and machines. d. none of these.