Suppose an underground reservoir of coal seam gas is located under properties owned by several different individuals.  As each well is drilled, it reduces the amount of coal seam gas that others canextract.  Compare how quickly the coal seam gas is likely to be extracted in this situation with how quickly it would be extracted if oneperson owned the property rights to drill for the entire seam of gas.  Be sure to use the economics terms and concepts that you have learned do far in your explanations.