This video teaches the concept of Trade, Exchange and Interdependence. People do not make everything that they and their family use: that is, they do not grow all their own food, sew their own clothes, build their own house and provide themselves personally with health care and education. Instead, people focus on a particular job and then use the wages that they earn from that job to purchase the goods and services they desire. In this way, an economy forms an interlinked network of trade, exchange and interdependence. The website contains an interactive quiz and links for related lesson plans.