Market activity that goes unreported either to avoid taxes or because the activity is illegal is called:

Money serves as a medium of exchange means that

A) it benefits both buyers and sellers. B) it eliminates the need for barter. C) it reduces transaction costs. D) All of the above are correct.

A time series graph reveals whether there is a ________ , which represents ________

A) trends in two variables; unrelated variables B) relationship between two variables; a trend in a variable C) cross-section relationship; a general tendency for the variables to rise or fall D) trend in a variable; a general tendency for the variable to rise or fall E) relationship between two variables; a cross-section relationship