Early humans migrated to the americas by crossing what

Beringia land mass is the correct answer.

Explanation:

The theory of crossing the Beringia was proposed in 1930's. But the genetic evidence show that the Native Americans don't have any genetic similarity with East Asians. The Bering land bride was the central part of Beringia and was up to 600 miles wide.The vegetation found in Beringia was shrub Tundra and was sufficient to support bighorn sheep and other small mammals. The wood and bark of the shrubs was used to light fire and keep the people warm in the bitter cold of Arctic winter. The humans started to migrate when the last ice age ended some 13,000 years ago. during this time global sea levels rose and the Beringia  region grew more warm and moist. The glaciers retracted and opened new routes for the into the continent , the paleo indians used these new routes to first enter into the Alaskan interior, then Yukon and in the end towards the arctic region.  The first evidence of humans beyond Bearing and in the interior of Alaska was 13,000 years ago.

the year 2019 marks the 2115th anniversary of his birth.