Why perfect market does not exist but we still study?

What is the most efficient market structure? What out come was not a result of the economic initiative taken by the Irish government in the 1990s? Is Logan county agricultural or industrial? Which people and which geographical areas do you think benefited most from social technological and economic changed from 1200 to 1500? What is macroecomics? What is joint demand? How did government spending affect the economy during the cold war? Advantages and disadvantages of the Factory system? When might it be desirable for a government to act as producer of goods and services with regards to economics? How much money does Gucci make a year? What are the injection into the circular flow of income? Role of public enterprise in national and economic development? Can you show me a pie graph of Mississippi main goods? What would 200 pounds sterling in 1996 be worth today? How much did it cost to make the humber bridge? How did Darius improve economic life in the Persian Empire? Could the sun be used economically as a source of energy in your area Why or why not? Which one of the following is not a long term objective of Indian planning? What is inflation-prone? Why is product possibility curve linear?