The increased output produced when one aditional person is hired. Note that this can be negative.

The marginal rate of transformation (MRT) of abatement costs into improved environment. It is the slope of the feasible frontier. […]

The change in consumption when disposable income changes by one unit.

The change in total imports associated with a change in total income.

The trade-off that a person is willing to make between two goods. At any point, this is the slope of […]

The quantity of some good that must be sacrificed to acquire one additional unit of another good. At any point, […]

The change in revenue obtained by increasing the quantity from Q to Q + 1.

The benefit (in terms of utility) of producing or consuming an additional unit of a good, taking into account both […]

The cost of producing an additional unit of a good, taking into account both the cost for the producer and […]

The additional utility resulting from a one-unit increase of a given variable.