Fact 1: Threatening behavior causes a fight-or-flight response in animals.

Fact 2: If a pony feels threatened it can respond with aggressive behavior.

Given the two facts above, answer the question "What sort of behavior can cause fight-or-flight responses?" with the following options: 
- hyperthyroidism
 - aggressive
 - hormones
 - humans
 - bullfrogs
 - hypothyroidism
 - similar
 - some mammals


 

  aggressive       