Systemic income inequality peaked at the time of the tech boom in the ________ and peaked again just ________.

The long-run supply curve of an industry equals the industry's

a. long-run marginal cost curve. b. the horizontal sum of all firms' supply curves at any point in time. c. long-run average cost curve. d. long-run total variable cost curve.

An example of an abstraction used in macroeconomics is

a. the price level. b. total costs. c. the tax rate. d. the treasury bill rate. e. proprietor's income.