36. C-10 USING A SUPPLY AND DEMAND DIAGRAM, DEMONSTRATE HOW A POSITIVE EXTERNALITY LEADS TO MARKET INEFFICIENCY. HOW MIGHT THE GOVERNMENT HELP TO ELIMINATE THIS INEFFICIENCY? DRAW A GRAPH. 37. C-11 RIVAL AND EXCLUDABLE: PRIVATE GOODS, NATURAL MONOPOLIES, COMMON RESOURCES, & PUBLIC GOODS. SEE EXAM IV, LAST PAGE. REPLACE (X) WITH LETTER UNDER APPROPRIATE SECTION RIVAL? YES NO YES Private Goods Natural Monopolies EXCLUDABLE? XXX XXX NO Common Resources Public Goods XXX XXX 38. C-19 EXPLAIN (3) THREE REASONS FOR ABOVE-EQUILIBRIUM WAGES.