Who lived in America before the Europeans arrived?

Why this is the answer

Native Americans, also called American Indians, are the answer, and USCIS accepts either name. When the first European ships crossed the Atlantic, the Europeans did not know that two continents lay between them and Asia, and they had no idea that millions of people already lived there. By then, according to the USCIS study guide, Native Americans had lived in North and South America for around 20,000 years. They were never a single nation. Each tribe had its own culture, religion, traditions, language and form of government. Some tribes moved from place to place and lived by hunting and gathering, others stayed put and farmed, and some built large cities with complex governments and written languages. The guide estimates that more than 50 million people lived across the Americas before the Europeans came, over 10 million of them on land that is now the United States. Diseases carried from Europe killed millions, and many others died in wars with the newcomers. By the 1600s about 6 million remained in the Americas, and about 1 million in North America. The first encounters were not all conflict. The Pilgrims settled in an area where the Wampanoag lived, and the Wampanoag taught them new ways of farming and how to grow corn, beans and squash. As more Europeans arrived and moved west, relations with some tribes turned tense and then violent, and the settlers took much of their land. Today there are more than 500 American Indian tribes in the United States, among them the Cherokee, Navajo, Sioux and Iroquois, all of which were already here when the Pilgrims landed. At the interview, keep the answer short. "Native Americans" or "American Indians" is complete, and you do not need to name a tribe. The usual mistake is to name the first Europeans instead: the Pilgrims, the Spanish or the French. They are the arrivals the question measures against, so they cannot be the people who were already living here. Picture the Wampanoag on the shore when the Pilgrims came in, and you will not mix up who was first.