The political system of the Soviet Union took place in a federal single-party soviet socialist republic framework which was characterized by the superior role of the Communist Party of the Soviet Union (CPSU), the only party permitted by the Constitution.
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.
