How and when do historians think that people first migrated to the Americas?

For more than half a century, the prevailing story of how the first humans came to the Americas went like this: Some 13,000 years ago, small bands of Stone Age hunters walked across a land bridge between eastern Siberia and western Alaska, eventually making their way down an ice-free inland corridor into the heart of ...

what is the question

i'm gonna go with d.

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