Fact 1: Earth 's magnetic patterns are used for finding locations by animals that migrate.

Fact 2: Bird Migration and Isotopes Tracking animal migration is a difficult task.

Given the two facts above, answer the question "What uses Earth 's magnetic patterns to find locations?" with the following options: 
- pigeons
 - cats
 - rats
 - elephants
 - Bats
 - salmon
 - birds
 - humans


 

       birds  