Answer:
Option a. As shown in the map, the Beringia Land Bridge used to separate the Bering Sea and Arctic Ocean.
Step-by-step explanation:
During the glacial periods, global sea levels dropped significantly, revealing land that has been previously covered by water in the form of ice. One of these lands was known as the Beringia Land Bridge, which was the floor of the Bering Sea that created a natural land bridge, that separated the Bering region from the Arctic Ocean. The bridge also worked as a connection land between Asia and North America as it is located on the west of the Lena River in Russia and the east of the Mackenzie River in Canada. The land bridge allowed the migration of species between the Americas and Eurasia, and as a result many species of plants, and animals were able to move from one continent to the other.