This document discusses several economic concepts including scarcity, opportunity cost, production possibilities curve (PPC), demand and supply. It defines scarcity as goods being desired more than their availability, forcing choices among alternatives. Limited resources like land, capital and human resources also contribute to scarcity. The document outlines necessities like food and clothing versus luxuries. It discusses money as a commodity like gold, representative money backed by gold, and current fiat money deemed legal tender by governments. It also explains how fractional-reserve banking and central banks like the Federal Reserve create money through lending and setting reserve requirements.