Which term describes animals that do not have backbones?

Which term describes animals that do not have backbones?

• A. Invertebrates
• B. Vertebrates
• C. Dam
• D. Atom

Answer: (A)

Having a backbone is the defining feature that separates vertebrates from other animals. Animals that do not have backbones are called invertebrates. This group includes insects, worms, snails, clams, and jellyfish—many different forms, but all share the absence of a vertebral column. Recognizing this distinction helps organize how scientists think about animal diversity and body plans. The other terms don’t describe this group: a dam is a female parent animal, a vertebrate is an animal with a backbone, and an atom is a basic unit of matter, not an animal classification.

Having a backbone is the defining feature that separates vertebrates from other animals. Animals that do not have backbones are called invertebrates. This group includes insects, worms, snails, clams, and jellyfish—many different forms, but all share the absence of a vertebral column. Recognizing this distinction helps organize how scientists think about animal diversity and body plans. The other terms don’t describe this group: a dam is a female parent animal, a vertebrate is an animal with a backbone, and an atom is a basic unit of matter, not an animal classification.