Select the vertebrate.

 - red-spotted purple butterfly
 - peacock mantis shrimp
 - peafowl
 - bull ant
A bull ant is an insect. Like other insects, a bull ant is an invertebrate. It does not have a backbone. It has an exoskeleton.
A peafowl is a bird. Like other birds, a peafowl is a vertebrate. It has a backbone.
A red-spotted purple butterfly is an insect. Like other insects, a red-spotted purple butterfly is an invertebrate. It does not have a backbone. It has an exoskeleton.
A peacock mantis shrimp is a crustacean. Like other crustaceans, a peacock mantis shrimp is an invertebrate. It does not have a backbone. It has an exoskeleton.