Please answer the following 1. At what points a profit-maximizing firm in perfect competition produces? What is a profit maximization rule?2. Discuss different market structure with respect to the level of difficulty or firms to enter the market3. What are the major barriers of entry in the monopoly market?4. Define an Oligopoly market and list its characteristics5. Define a perfect competition market and list its characteristics6. What do you about price and marginal revenue in perfect competition?7. Define break-even situation for a firm? When do a firm achieve a break-even?8. Compare and contrast perfect competition and a monopoly with respect to price and quantity produced9. What is a horizonal merge?10. What is a vertical merger?11. What is four-firms concentration ratio? How do you interpret the value?12. Define the HHI index (Herfindahl indexes)? How do you calculate the HHI index?