Which statement describes animals without backbones?

Which statement describes animals without backbones?

• A. Arthropod
• B. Invertebrate
• C. Mollusk
• D. Vertebrate

Answer: (B)

Animals without backbones are described as invertebrates. The backbone, or vertebral column, is what separates vertebrates from invertebrates. Vertebrates include animals with a spinal column—like fish, birds, mammals, reptiles, and amphibians. Invertebrates cover a huge variety of animals that lack that backbones, such as insects and spiders (arthropods), snails and clams (moss or mollusks), worms, starfish, and more. Among the options, arthropod and mollusk refer to specific groups within invertebrates, not the general idea of all animals without backbones. Vertebrate describes animals that do have backbones. So the best fit is invertebrate.

Animals without backbones are described as invertebrates. The backbone, or vertebral column, is what separates vertebrates from invertebrates. Vertebrates include animals with a spinal column—like fish, birds, mammals, reptiles, and amphibians. Invertebrates cover a huge variety of animals that lack that backbones, such as insects and spiders (arthropods), snails and clams (moss or mollusks), worms, starfish, and more. Among the options, arthropod and mollusk refer to specific groups within invertebrates, not the general idea of all animals without backbones. Vertebrate describes animals that do have backbones. So the best fit is invertebrate.