Changes in taxes and spending by the executive and legislative branches of a country's government that can be used to either stimulate or restrain the economy are called:

An increase in the money supply

a. and an investment tax credit both cause aggregate demand to shift right. b. and an investment tax credit both cause aggregate demand to shift left. c. causes aggregate demand to shift right, while an investment tax credit causes aggregate demand to shift left. d. causes aggregate demand to shift left, while an investment tax credit causes aggregate demand to shift right.

The primary copper industry in the United States would be an example of a:

A. homogeneous oligopoly. B. differentiated oligopoly. C. noncollusive oligopoly. D. duopoly.