1. Under a command economy, the government decides what and how much is produced through central planning rather than corporations or consumers. 2. When evaluating waiting in line for 3 hours for a free hamburger, the opportunity cost of that person's time was not considered, as well as the tradeoffs other consumers were making. 3. Improving one's GPA provides the incentive of increased opportunity through scholarships and potentially lower student loan interest rates. 4. Economists think at the margin by analyzing how small changes at the boundary, or margin, of economic decisions can impact the overall situation, such as how a small increase or decrease in price can impact the quantity demanded of a product.