According to economic historians, streetcars in southern cities in the early 1900s were racially segregated because the owners of the firms believed that segregation raised the firms' profits

When the Federal Reserve sells a government security to a commercial bank

A) the cash reserves of the commercial bank decrease. B) the net worth of the commercial bank increases. C) the loans of the commercial bank will increase. D) the balance sheet of the commercial bank is thrown off balance.

Suppose that firms in a competitive industry are earning positive economic profits. All else equal, in the long run, we would expect the number of firms in the industry to

a. increase. b. decrease. c. remain the same. d. We do not have enough information with which to answer this question.