K Term Margin: a unit in . When you think at margin, you decide to that additional of resource on a particular want or need. -) Imagine that you have $360. You have various , such as buying a new pair of shoes, paying your monthly car loan installment, and saving for college. ) As a rational person, you 0 would Q would not spend the entire amount on just one need. Instead, you would spend money on shoes, make your loan payment, and save the for college. -) But you may choose to spend a little on the shoes by saving a little for college. -> This shows that you are thinking People, businesses, and governments do don't use a scarce resource entirely to fulll a need. Instead, they choose to use one more unit of the resource on a need. That means they one unit of the resource for need