They all live on land. They all have hair or fur. They are all good swimmers. They all live in warm climates.
I gave my students this multiple choice question: Nicole is learning about the characteristics of different vertebrates. Which is a common characteristic of mammals?

Only one answer is correct among these 4 choices:
- They all live on land.
- They all have hair or fur.
- They are all good swimmers.
- They all live in warm climates.

Could you tell me which one is correct?

They all have hair or fur.