Among the choices posted, the best and only sensible answer is: the search for food items. The Asians who crossed the Bering Strait did not need to spread religion, to bring slaves from Africa nor the desire to conquer new peoples.
It would be that they provide ritual obligations that need to be followed.
They knew that people were going to change, and that the Constitution had to change with them. In order to be a working document, it had to be changed to reflect what was going on. At the same time they wanted changes to be taken seriously so they made it difficult to change things.
All U.S. military services use drones, not all of the same type though. They use certain drones for certain things. The MQ-4 Triton is a variant of the U.S. Air Force. It is high altitude, long endurance, designed to collect intelligence for long periods of time.
