What is an historical theory versus fact about ancient American civilization A people walked across the Bering Strait during the ice age B in the ice age the Bering Strait was above sea level

For ancient American civilization, scientists speculate that peoplewalked across the Bering Strait during the ice age. This wouldexplain HOW Native Americans were on the North and South Americancontinents long before the discovery of the New World. They basethis theory on the fact that in the ice age the Bering Strait wasabove sea level.
An opposing theory might be that Native Americans were on thecontinent before Pangaea completely broke apart.