1. Using your notes and the book, examine each of the barriers to entry and explain which are artificial or natural. If the monopoly is considered a social bad, what can the government do to protect us?

2.Is monopolistic competition a monopoly market or a competitive market? List at least four of the ways firms can differentiate a product (also called nonprice competition). Then give an example for each.

1. Draw and explain the prisoner's dilemma model. What key concept does the model show?