Policy proposals to reduce carbon emissions would limit companies’ allowed emissions. If a company chooses to exceed emission limits, it could purchase emission permits from other lower emitting companies. This market-incentive policy tool is called ______.

The writers of the Constitution established a federal system of government in part because

A. few states in history had successfully established unitary governments. B. the British political system was based on the federal principle. C. the states would be valuable sources of revenue for a federal government. D. Locke and Montesquieu had concluded it was superior to other systems of government. E. the states already existed as established entities and had to be preserved.

The greatest military costs for the U.S. have been incurred in which of the following conflicts?

A. World War I B. World War II C. Korea D. the post-9/11 conflicts E. Vietnam