Polar Bears

Polar bears are [classified (classify)] as marine mammals(海洋哺乳动物). They spend most of their [41 (life)] on the sea ice of the Arctic Ocean. They have a lot of body fat that [42 (prevent)] them from the cold air and water. Considered [43 (skill)] swimmers, they can swim six miles per hour. Polar bears spend over 50% of their time [44 (hunt)] for food, but less than 2% of their hunts are [45 (success)]. Because they need a large amount of fat to survive, their diet [46 (main)] consists of seals. The total polar bear population is [47 (divide)] into 19 units. Of those, the [48 (late)] data from scientific research show that there is a high risk of future decrease. Because of continuing loss of their sea ice habitat （栖息地） [49 (result)] from climate change, polar bears were listed as a threatened animal. Therefore, the [50 (protect)] of polar bears' habitat needs to be dealt with as soon as possible.