<Dt> Goods are available in all quantities </Dt> <Dd> It is assumed that a consumer may choose to purchase any quantity of a good (s) he desires, for example, 2.6 eggs and 4.23 loaves of bread . Whilst this makes the model less precise, it is generally acknowledged to provide a useful simplification to the calculations involved in consumer choice theory, especially since consumer demand is often examined over a considerable period of time . The more spending rounds are offered, the better approximation the continuous, differentiable function is for its discrete counterpart . (Whilst the purchase of 2.6 eggs sounds impossible, an average consumption of 2.6 eggs per day over a month does not .) </Dd> <P> Note the assumptions do not guarantee that the demand curve will be negatively sloped . A positively sloped curve is not inconsistent with the assumptions . </P> <P> In Marx's critique of political economy, any labor - product has a value and a use value, and if it is traded as a commodity in markets, it additionally has an exchange value, most often expressed as a money - price . Marx acknowledges that commodities being traded also have a general utility, implied by the fact that people want them, but he argues that this by itself tells us nothing about the specific character of the economy in which they are produced and sold . </P>

Who decide(s) what goods and services will be produced