A yard sale is an example of a market

The U.S. dollar is one of the leading reserve currency in the world. This means that

A) dollars are often used to settle international debts and to state other currency exchange values. B) dollars are the most common currency for savings internationally. C) dollars are held to cover shortfalls in government budgets. D) dollars are accepted in just about every country in the world.

If the price of an input falls, a firm would increase the use of that input for two reasons:

a. The input is now more productive, and the firm can substitute this input for other relatively more expensive inputs. b. The input is now more productive, and overall production costs are now lower, meaning a firm may choose to increase production. c. Overall production costs are now lower and the firm can substitute this input for other relatively more expensive inputs. d. Overall production costs are now lower and the firm will have more of other inputs to use with the one in question.