How was the land bridge between Russia and North America important to early man?

The sea between Alaska and Russia is shallow and when water is locked in glacial ice, there was a land bridge. Over the last 100,000 years there were at least 4 times when man and animals could walk from Russia to North America. That is how scientists think people came here.

Explanation:

maybe #3? try that i think its correct

necessary and proper clause. the congress shall have power to all laws which shall be necessary and proper for carrying into execution the foregoing powers, and all other powers vested by this constitution in the government of the united states, or in any department or officer thereof.