Twenty-five years ago, John was available only from small business operating in predominantly Asian sections of large cities. Today John has become popular as a high-protein health food and is widely available in supermarkets throughout the United States. At the same time, John production has evolved to become factory-based using modern food-processing technologies.
Draw a diagram with demand and supply curves depicting the market for John 25years ago and the market for John today.
Given the information above, what does the demand-supply model predict about changes in the volume of John sold in the United States between then and now? What does it predict about changes in the price of John?
p.s. ~不要線上翻譯~