You are presented with the quiz "Migratory animals are dependent on what feature of the interior of the Earth for navigation?" 

But you don't know the answer, so you turn to your teacher to ask for hints. He says that "earth 's magnetic patterns are used for finding locations by animals that migrate" and "earth s rotation and iron core creates a magnetic field much like giant magnet". 

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


 

 rotating iron core          