Threatening behavior by predators causes a porcupine to extend its quills, and porcupine quills can be extraordinarily painful. Given these facts, what can cause predators pain among 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   