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

Fact 2: Boreal and temperate species have generally survived by migrating.

Given the two facts above, answer the question "How do boreal species ensure their survival?" with the following options: 
- Staying put
 - population movement
 - Leaving children behind
 - Earth's magnetic field
 - Going to work
 - food and shelter
 - genetic diversity
 - looseness of dirt or compost


 

    Earth's magnetic field     