In a previous lesson we introduced the law of supply and the determinants of supply, but we never clearly explained WHY there is a direct relationship between price and quantity supplied. In this lesson we will connect the law of supply to a law introduced in an earlier lesson on the PPC and the Law of Increasing Opportunity Costs (http://www.econclassroom.com/?p=4403). The concept of increasing marginal costs of production will be explained and the link between firms' marginal costs and supply will be established in this lesson. Want to learn more about economics, or just be ready for an upcoming quiz, test or end of year exam? Jason Welker is available for tutoring, IB internal assessment and extended essay support, and other services to support economics students and teachers. Learn more here! http://econclassroom.com/?page_id=5870