In perfect competition, 0 A. advertising can be used to differentiate a product or service. 0 B. a business always hires many workers. 0 C. many sellers produce an identical product or service. 0 D. there are no close substitutes. In the market structure of monopoly, O A. market power is low and the elasticity of demand is high. O B. market power is high and the elasticity of demand is low. 0 C. market power is high and the elasticity of demand is high. 0 D. market power is low and the elasticity of demand is low- Barriers to entry 0 A. are a limit on business prots. 0 B. make people buy more of a good than they really want. O C. enable monopolists to earn economic prots in the long run. 0 D. are an attempt to distinguish a product or service from those of competitors. One of the characteristics of market structure is O A. monOpoly. O B. government intervention in markets. 0 C. barriers to entry of new competitors- 0 D. the regulations in an industry