1.whether a firm stays in business or shuts down depends hea

1.whether a firm stays in business or shuts down depends heavily on the concept of
a Economic profit
b Actual profit
c Market profit
d Concentration ratios
2.Economic theory would suggest that the profitability of an industry would be
a directly related to the number of firms competing in the industry.
b Inversely related to the number of firms competing in the industry
c Unrelated to the number of firms competing in the industry
d zero in the long run,regardless of market structure.
3 Under perfect competition,the supply curve is
a The marginal cost curve for all price quantity combinations.
b The marginal cost curve,but only that portion that is downward sloping.
c The marginal cost curve,but only that portion that is upward sloping.
d The marginal cost curve,but only that portion that is above the minimum of average variable cost.
4 In a diagram of perfect competition,the marginal revenue line moves up and down when there is exit and entry,respectively,because
a The market demand for the good rises and falls when there is exit and entry,respectively.
b The market demand for the food rises and falls when there is entry and exit,respectively.
c The market supply for the good rises and falls when there is exit and entry,respectively
d The market supply for the good rises and falls when there is entry and exit,respectively
5 If MR>MC,then when an additional unit is sold,the firm's
a profit will be positive
b profit will increase
c profit will be negative
d profit will decrease.