waterproof fur webbed hind feet large, sharp teeth flat, wide tail
I gave my students this multiple choice question: Beavers build their homes in ponds and streams. Which characteristic is least critical to building homes in an aquatic environment?

Only one answer is correct among these 4 choices:
- waterproof fur
- webbed hind feet
- large, sharp teeth
- flat, wide tail

Could you tell me which one is correct?

large, sharp teeth