Which of the following is NOT one class of a market structure?

The gap in GDP between the United States and Europe can be explained by the fact that

A) income taxes are higher in the United States. B) prices are higher in the United States. C) equilibrium employment is higher in Europe. D) the Okun Gap is larger in the United States. E) U.S. labor is more productive than European labor.

Refer to Table 2-4. What is George's opportunity cost of mowing a lawn?

A) one-half of a garden cultivated B) two lawns mowed C) two-thirds of a garden cultivated. D) one and a half lawns mowed