You are presented with the question "What stays warm in winter?" and the following answer choices: 
- bushes
 - snakes
 - fur seals
 - lizards
 - Conifers
 - bullfrogs
 - some mammals
 - fish

Now knowing that some animals' fur grows thicker for staying warm in the winter and fur seals grow a thick undercoat of fur, used as insulation, choose the best answer.


 

   fur seals      