I'm struggling in this question, please help me explain. Thank you so much!

1. Explain why firms operating in monopolistically competitive markets probably will not earn an economic profit in the long run, and explain why they might.
2. Does a monopolistically competitive firm exhibit resource-allocative efficiency? Explain your answer.
3. State the three assumptions common to the different theories of oligopoly.
4. Concentration ratios have often been used to note the tightness of an oligopoly market. A high concentration ratio indicates a tight oligopoly market, and a low concentration ratio indicates a loose oligopoly market. Would you expect firms in tight markets to reap higher profits, on average, than firms in loose markets? Would it matter if the markets were contestable? Explain your answers.