The correct answer is: They have thick fur to keep them warm.
Polar bears have adapted to living in the Arctic by having a thick layer of fur and a layer of blubber beneath their skin. This insulation helps them to maintain their body heat in the extreme cold of the Arctic. The thick fur also helps to repel water and snow, keeping the polar bear dry and warm.
Polar bears do not have wings, and while they can swim, they do not have large ears to hear predators.