1. Which of the following is a direct exchange?

		purchasing a soda from a vending machine
		bidding on a painting at an auction
		trading your bicycle for an iPhone
		buying groceries in a supermarket
		bidding on an antique radio on eBay

1. When Bob has a lower opportunity cost for mowing a lawn than Jim has, Bob is said to have what?

		a comparative privilege
		a comparative advantage
		a real advantage
		a direct advantage