What is the difference between the physical supply and the economic supply of a non-renewable resource? Why have predictions that non-renewable resources would be depleted failed to occur? What does Hotelling’s rule imply about the change in resource rents over time? What three factors contributed to the expansion of global non-renewable resource consumption through the twentieth century? What are the four stages in consumption and prices of a non-renewable resource over time? Will we likely ever "run out" of a non-renewable resource? How would internalized costs affect the turning point of a non-renewable resource? What does the Second Law of Thermodynamics imply about recycling? What policies can be used to achieve the optimal level of recycling? What is meant by "technological lock-in"? What can be done to avoid the problem?