Vertebrata refers to animals with what characteristic?

• A. No backbone
• B. A backbone
• C. A segmented exoskeleton
• D. Only aquatic forms

Answer: (B)

Vertebrata refers to animals that have a backbone, the vertebral column that protects the spinal cord and provides internal support. This internal skeleton, made of bone or cartilage, allows greater size and more complex movement compared with animals without backbones. The other options don’t fit: having no backbone describes invertebrates; a segmented exoskeleton is typical of arthropods, not vertebrates; and vertebrates include both aquatic and terrestrial species, so being limited to aquatic forms isn’t correct.