Final answer:
The Sixteenth Amendment resolved the reforms needed by authorizing a federal income tax in the United States.
Step-by-step explanation:
The Sixteenth Amendment resolved the reforms needed by authorizing a federal income tax in the United States. Prior to this amendment, the national government primarily relied on tariffs as their main source of revenue. However, this pushed up the prices of goods for the working poor. The income tax introduced by the Sixteenth Amendment was a progressive tax, meaning that higher incomes were taxed at a higher rate than lower incomes. This helped to address the issue of income inequality and provided a more stable source of revenue for the government.