Final answer:
Native Americans originated from Eurasia, migrating across a land bridge called Beringia to North America in search of food and later populating the entire Americas.
Step-by-step explanation:
The Native Americans are believed to have migrated from Eurasia. This migration occurred via a land bridge known as Beringia that connected Asia and North America around 9,000 to 15,000 years ago. They migrated in search of food sources, following the megafauna of the era, such as mammoths and mastodons. As the glaciers melted and the sea levels rose, this land bridge was submerged, forming the Bering Strait. Continuing their journey, these peoples moved southward, eventually populating both North and South America. This migration shaped the development of diverse cultures and civilizations across the Americas. Additional theories suggest that coastal migration routes were also utilized by these early settlers.