Final answer:
The Bering Land Bridge migration model is the oldest and most widely accepted theory regarding the origins of Native Americans in the Americas.
Step-by-step explanation:
The Bering Land Bridge migration model is the oldest and most widely accepted theory regarding the origins of Native Americans in the Americas. This theory suggests that during the last ice age, humans were able to migrate from Siberia to Alaska by crossing over the land bridge that was revealed due to dropping sea levels. This migration occurred in multiple waves over a period of time and was driven by the migration of megafauna. While there are alternate theories, such as the Solutrean hypothesis, the Bering Land Bridge model is supported by genetic studies and archaeological evidence.