Why is the supply curve drawn as a vertical straight line in Figure 3.8?
 What are the arguments for and against making the sale of alcoholic  drinks illegal?  To what extent can an economist help to resolve the  issue?
 Why don't farmers benefit from a high income elasticity of demand for convenience foods?
 The income elasticity of demand for milk is negative (an 'inferior' good). What is the implication of this for milk producers?
 Why do pork and lamb have relatively high price elasticities of demand  compared with the other foodstuffs in the table? What are the  implications of this for the relative stability or instability of the  prices of pork and lamb compared with other foodstuffs?