In order for a market to work efficiently as possible, two things must occur. (1) Each person within the market must be able to evaluate choose your answer.. costs of participation. These are costs that only the individual participant pays. (2) choose your answer.. costs are the costs of a market activity imposed on people who are not active participants within the market. choose your answer.. costs are equal to the sum of internal costs and external costs that result from a market activity. A/An externality exists when an choose your answer... V cost or benefit deviates from a choose your answer... cost or benefit