have hair lay eggs have webbed feet breathe with gills
I gave my students this multiple choice question: Which characteristic applies to animals in only one of these taxonomic groups: reptiles, mammals, birds, amphibians, or fishes?

Only one answer is correct among these 4 choices:
- have hair
- lay eggs
- have webbed feet
- breathe with gills

Could you tell me which one is correct?

have hair