Which category includes clams?

Which category includes clams?

• A. Vertebrate
• B. Fish
• C. Invertebrate
• D. Mammal

Answer: (C)

Think about how animals are grouped by whether they have a backbone. Having a backbone makes you a vertebrate. Clams do not have a backbone; they are soft-bodied animals covered by a shell and belong to mollusks, which are invertebrates—the group of animals without backbones. That’s why clams aren’t fish or mammals, both of which are vertebrates with backbones. So the best choice is the invertebrate category.

Think about how animals are grouped by whether they have a backbone. Having a backbone makes you a vertebrate. Clams do not have a backbone; they are soft-bodied animals covered by a shell and belong to mollusks, which are invertebrates—the group of animals without backbones. That’s why clams aren’t fish or mammals, both of which are vertebrates with backbones. So the best choice is the invertebrate category.