In economics, the study of the decisions of firms in industries where the profits of each firm depend on its interactions with other firms is called

Monopolies arise when there are

A) many substitutes but there are no barriers to entry. B) no close substitutes and there are no barriers to entry. C) no close substitutes and there are barriers to entry. D) many substitutes and there barriers to entry. E) None of the above answers are correct because the existence of a monopoly has nothing to do with the presence or absence of barriers to entry.

Which of the following would shift a nation's production possibilities frontier outward?

A) discovering a cheaper way to convert sunshine into electricity B) an increase in demand for the nation's products C) a decrease in the unemployment rate D) a law requiring workers to retire at age 50