<P> Forms include monopoly (in which there is only one seller of a good), duopoly (in which there are only two sellers of a good), oligopoly (in which there are few sellers of a good), monopolistic competition (in which there are many sellers producing highly differentiated goods), monopsony (in which there is only one buyer of a good), and oligopsony (in which there are few buyers of a good). Unlike perfect competition, imperfect competition invariably means market power is unequally distributed . Firms under imperfect competition have the potential to be "price makers", which means that, by holding a disproportionately high share of market power, they can influence the prices of their products . </P> <P> Microeconomics studies individual markets by simplifying the economic system by assuming that activity in the market being analysed does not affect other markets . This method of analysis is known as partial - equilibrium analysis (supply and demand). This method aggregates (the sum of all activity) in only one market . General - equilibrium theory studies various markets and their behaviour . It aggregates (the sum of all activity) across all markets . This method studies both changes in markets and their interactions leading towards equilibrium . </P> <P> In microeconomics, production is the conversion of inputs into outputs . It is an economic process that uses inputs to create a commodity or a service for exchange or direct use . Production is a flow and thus a rate of output per period of time . Distinctions include such production alternatives as for consumption (food, haircuts, etc .) vs. investment goods (new tractors, buildings, roads, etc .), public goods (national defence, smallpox vaccinations, etc .) or private goods (new computers, bananas, etc .), and "guns" vs "butter". </P> <P> Opportunity cost is the economic cost of production: the value of the next best opportunity foregone . Choices must be made between desirable yet mutually exclusive actions . It has been described as expressing "the basic relationship between scarcity and choice". For example, if a baker uses a sack of flour to make pretzels one morning, then the baker cannot use either the flour or the morning to make bagels instead . Part of the cost of making pretzels is that neither the flour nor the morning are available any longer, for use in some other way . The opportunity cost of an activity is an element in ensuring that scarce resources are used efficiently, such that the cost is weighed against the value of that activity in deciding on more or less of it . Opportunity costs are not restricted to monetary or financial costs but could be measured by the real cost of output forgone, leisure, or anything else that provides the alternative benefit (utility). </P>

The idea that economic political and other forms of human behavior