Select the vertebrate.

 - bull ant
 - pipevine swallowtail butterfly
 - puffin
 - rock lobster
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 rock lobster is a crustacean. Like other crustaceans, a rock lobster is an invertebrate. It does not have a backbone. It has an exoskeleton.
A puffin is a bird. Like other birds, a puffin is a vertebrate. It has a backbone.
A pipevine swallowtail butterfly is an insect. Like other insects, a pipevine swallowtail butterfly is an invertebrate. It does not have a backbone. It has an exoskeleton.