Question

What is the most widely accepted theory on how early humans migrated to North America?

Because of the Ice Age, they were able to walk from Australia to the southern tip of South America.
They used boats to cross the ocean from Australia to the southern tip of South America.
They used boats to cross what’s now called the Bering Strait.
They walked across the Bering Strait, which was a land bridge at the time.

Answer 1

They walked across the Bering Strait, which was a land bridge at the time.

During the last Ice Age sea levels were much lower, exposing a landmass called Beringia between Siberia and Alaska. Most archaeologists consider migration across that land bridge (and then southward into the Americas) the primary route, though there is growing evidence that some groups may also have used coastal boat routes.