Final answer:
The 16th Amendment to the U.S. Constitution authorized the imposition of a Federal income tax.
Step-by-step explanation:
The 16th Amendment to the U.S. Constitution authorized the imposition of a Federal income tax. This amendment was put into place to replace the revenue that tariffs had previously supplied to the federal government. The income tax is a progressive tax, meaning that those with higher incomes are taxed at a higher rate than those with lower incomes.