True$/$False

Indicate whether the statement is true or false.

$\_\_\_\_21.$ Economics is the study of how evenly goods and services are distributed within society.

$\_\_\_\_22.$ Choosing not to attend a concert so that you can study for your exam is an example of a tradeoff.

$\_\_\_\_23.$ The cost of an action is measured in terms of foregone opportunities.

$\_\_\_\_24.$ A marginal change is a small incremental adjustment to an existing plan of action.

$\_\_\_\_25.$ A tax on gasoline is an incentive that encourages people to drive smaller more fuel$-$efficient cars.

$\_\_\_\_26.$ For economists, conducting experiments is often difficult and sometimes impossible.

$\_\_\_\_27.$ Good assumptions simplify a problem without substantially affecting the answer.

$\_\_\_\_28.$ A circular$-$flow diagram is a visual model of the economy.

$\_\_\_\_29.$ In the circular$-$flow diagram, one loop represents the flow of goods, services, and factors of production, and

the other loop represents the corresponding flow of dollars.