The markets are different, without these different markets, there would be no structure. By being able to understand different markets and their language, such as demand, supply, average variable cost and marginal costs, we can better prepare for the economic and financial future. Market structure and the interaction that occurs can be defined by the number of firms and the obstacles new firms encounter when entering a particular market. Perfect competition, monopoly, monopoly, and oligopoly are four forms of market structures recognized by economists. Compare and Contrast Public goods are inherently non-excludable (you can't stop people from enjoying the good or it costs too much to do so) and non-excludable. rival (when one person consumes the good, this does not reduce the satisfaction that another can receive from the good). A classic example is that of “national defense”. The fact that someone can benefit from a national defense unity does not prevent anyone else from enjoying the same unity and does not diminish the satisfaction you feel from enjoying it. Private goods are excluded, such as food, clothing, toys, furniture, and cars, which are types of goods that can be rivalrous or non-rivalrous. For example, rival goods are types of goods whose consumer at the same time prevents the use of goods, durable goods and their use can be shared with others, such as moss, however, in contrast, rival goods can be unbearable like food, once consumed it cannot be reused. In contrast, nonrival goods can be consumed by the consumer and will not prevent their simultaneous consumption by others. These types of products are shown on television because their use in one location does not prevent them from being used in other locations. Natural monopoly represents the only ...... middle of paper ...... continually differentiate their products so that they achieve economic profit. Market structure and the interaction that occurs can be defined by the number of firms and the obstacles new firms encounter when entering a particular market. edition). Boston: Irvin/McGraw-Hill, 2008. Department of Economics (nd). Labor market balance. , Accessed January 19, 2010, from http://faculty.washington.edu/ezivot/econ301/labor_market_equilibrium.htmPeasrson Edication, Inc. (1995-2010). Retrieved February 21, 2010 from http://wps.prenhall.com/bp_casefair_econf_7e/30/7931/2030537.cw/index.htmlSparksnotes Editors (nd). Sparknote on work request. Retrieved January 19, 2010 from http://www.sparknote.com/economys/micro/labormarkets/labordemand/