When a competitive firm doubles the quantity of output it sells, its

In the short run, the point at which diminishing marginal returns to labor begin is the point at which the marginal cost curve

A) peaks. B) bottoms out. C) is upward sloping. D) is downward sloping.

From the 1950s to the 1980s, union membership in the United States, measured as a percentage of the labor force, remained fairly constant at

a. 10 percent b. 18 percent c. 25 percent d. 36 percent e. 55 percent