Threatening behavior causes a fight-or-flight response in animals, and fear also causes adrenaline to surge, which is part of the fight or flight response. Given these facts, threatening behavior causes among the following options:
- to move people
 - population movement
 - adrenaline to surge
 - hypothyroidism
 - a pathogens
 - Plant growth is reduced
 - Greenhouse gasses
 - hyperthyroidism


 

   adrenaline to surge      