You are presented with the quiz "What prevents the transfer of heat from an organism's body?" 

But you don't know the answer, so you turn to your teacher to ask for hints. He says that "preventing the transfer of heat from an organims 's body causes that organism to keep warm" and "if Arctic foxes are in too cool weather, they warm up by their thick fur". 

So, what's the best answer to the question?


 

      fur     