How does a polar bear protect itself?

Polar bears are very strong.

They have large teeth and claws with an Excellent sense of smell.
thick coat plus a thick layer of fat protects them from cold teeth, claws and sheer mass is good for defending yourself although I cant think of any natural enemies they have...
blend in the snow
b being bigger than anything else in the arctic
They protect themselfs by growing thick fur, and long,sharop claws.(and teeth)
they use their teeth
They fight with their sharp teeth and claws