Polar Bear
作者:pdcmoe etd
1. wide paws
1.1. move around easily in the ice
2. cover their nose when they sleep
2.1. keep it warm
3. nostril closes in water
3.1. prevent water from getting in
4. rub against ice
4.1. to cool the body down
5. white fur
5.1. camoflage from enemy
6. thick fur
6.1. keep them warm
7. thick layer of fat
7.1. keep them warm