Which description best defines the field of economics? a. the study of the four factors of production b. the study of how nations decide what to produce c. the study of how people use scarce resources to meet unlimited wants d. the study of opportunity costs

In the short-run, marginal costs are equal to the change in variable costs as output changes. ( mc = change in variable cost / change in quantity) assume that capital is fixed in the short-run. (a) start with the equation for marginal cost and derive an equation that relates marginal cost of production to the cost and productivity of labor. (b) draw a standard looking short-run marginal cost curve and use the equation you derived to explain its shape.