Which of the following animals is a vertebrate?

What do we have in common with sharks, bluebirds, lizards, and toads? We are all vertebrates, or animals with backbones. Vertebrates use their backbones for movement and support. Vertebrates share other traits as well: an internal skeleton, muscles, a protective skin, blood that circulates through vessels, and an advanced nervous system, including a head with a brain.
Which of the following animals is a vertebrate?
jellyfish
banana slug
lovebird
Lovebirds have backbones just like you and me. Vertebrates include five major groups: amphibians, fish, reptiles (like snakes and turtles), birds, and mammals.
Invertebrates have an exoskeleton. Vertebrates have:
an endoskeleton
a mixoskeleton
no skeleton at all
All vertebrates have an endoskeleton -- their bones are inside their bodies. When humans and other vertebrates grow, their bones grow with them. Invertebrates that have exoskeletons, like arthropods, must shed their exoskeletons as they grow.
Vertebrates can be both warm-blooded and cold-blooded.
Some vertebrates are warm-blooded. Their body temperature stays the same. Others have a body temperature that changes, depending on the temperature of their surroundings.
A giraffe's neck contains more vertebrae, the individual bones that make up the spine, than any other mammal on Earth.
Giraffes have the same number of vertebrae as most other mammals. The spine of a giraffe is made up of seven vertebrae just like ours -- they are just longer!
Phylum and subphylum: Chordata, Vertebrata
Characteristics: a backbone, an advanced nervous system, skin, an internal skeleton, muscles
Habitats: found in all ecosystems around the world, from the polar regions to the tropics