a. For each of the following goods, give your best estimate of its most likely degree of rivalness and (relative) exclusion cost, using the definitions of these variables and the information in the course notes on externalities and public goods. Explain carefully how you get your estimates. Plot the goods in a graph with rivalness on the horizontal axis and (relative) exclusion cost on the vertical axis.

(1) 1000 pounds of compacted scrap steel; (2) 1/2 ton of compacted scrap steel; (3) a mahogany tree in an inaccessible Central American rain forest; (4) a mahogany tree next to a new highway through a Central American rain forest; (5) service provided by a nearly empty bus on its daily route.