In a general equilibrium model, a tax on a single factor in its use only in a particular sector can affect returns to all factors in all sectors.

The market supply curve for labor in a perfectly competitive labor market:

A) is horizontal or perfectly elastic. B) is vertical or perfectly inelastic. C) can be derived by vertically adding the individual supply curves of labor. D) can be derived by horizontally adding the individual supply curves of labor.

If a country's currency is "pegged" to the dollar, its exchange rate is

A) floating. B) flexible. C) undervalued. D) fixed.