Q7.Explain what is meant by self-interest and how it helps achieve society's economic goals? Why is there such a wide variety of goods and services produced in a market system? In what way are entrepreneurs and businesses at the helm of the economy, but commanded by consumers?

Q8. What are externalities and explain how they create demand-side failures and supply-side failure? Give an example of each type of externality. What can governments do to reduce positive and negative externalities?