When a firm's profit maximizing sales level is positive, its marginal revenue is ______ its marginal cost at that quantity.

A trade deficit refers to a situation where:

A. Government spending (including transfer payments) exceeds tax revenues B. A nation's purchases from other nations are less than its sales to other nations C. Assets are less than liabilities D. Exports are less than imports

The short-run aggregate supply curve is upward sloping for all of the following reasons except:

A. some markets are posted-price markets. B. some firms adjust their markup in response to an increase in demand. C. all inputs are fully utilized in the short run. D. some firms adjust their production in response to an increase in demand.