Mammals, birds, reptiles, and fish are vertebrates because they have a jointed backbone. True or False?

• A. True
• B. False
• C. Not sure
• D. Both

Answer: (A)

Vertebrates are animals defined by having a backbone, the spine made of vertebrae. Mammals, birds, reptiles, and fish all possess backbones—the vertebral column is a chain of bones or cartilage that protects the spinal cord and provides structural support. Because each of these groups has a spine, they are classified as vertebrates. The statement is true. Other options like not sure or both don’t fit a true/false question, since the fact is either true or false and here it is true.