Which of the given feature helps the Polar bear to swim efficiently?

Polar bears are found exclusively in the Arctic region around the North pole. Their body shows many modifications to survive in the bitter cold of polar regions.

The polar bear's front paws are big and serve as propellers to push the animal through the water to give it speed. This feature makes them not only good swimmers but also fast swimmers. They can swim at a speed of approximately 10 kilometers per hour.  Being fast swimmers they can efficiently catch their prey like seals in the water. 

Polar bears can close their nostrils and stay underwater for long periods while swimming.