Fact 1: Threatening behavior by predators causes a porcupine to extend its quills.

Fact 2: Porcupine quills can be extraordinarily painful.

Given the two facts above, answer the question "What can cause predators pain?" with the following options: 
- animals with backbones
 - Staying away from porcupine
 - Ignoring porcupine
 - pressure on the skin
 - Befriending porcupine
 - Threatening behavior towards porcupine
 - Something with a head, thorax, and abdomen
 - the body's largest organ


 

      Threatening behavior towards porcupine   