Question

Sea urchins are spiny, globular animals that live on the ocean floor. How are sea urchins classified?

A. vertebrates

B. invertebrates

C. mammals

D. arthropods

Answer 1

B

Step-by-step explanation:

They have no bones, and therefore, they are classified as a invertebrate(s).

Answer 2

B

Step-by-step explanation:

because they belong to classe Echinoidea, phylum echonodermata