Threatening behavior by predators causes a porcupine to extend its quills, and porcupines are in the rodent family. Given these facts, what extends something because of threatening behavior by predators among the following options:
- influenza
 - chickenpox
 - A rodent
 - A primate
 - A treeshrew
 - fur and fat
 - A flying lemur
 - an object


 

   A rodent      