What does the reference to the United States' ,begin emphasis, centennial, end emphasis, help the reader understand about the creation of Yellowstone National Park? 1. Yellowstone National Park was established as a way of celebrating the hundredth anniversary of the United States.

2.People had lived in the Yellowstone area of the United States for almost 100 years before it became the world's first national park.

3.Other nations would follow the example set by the United States and establish their own national parks on their hundredth anniversaries.

4. The United States government had the vision to create the world's first national park, even though the country was less than 100 years old.