| A | B |
|---|
| chelicerates | Spiders, scorpions, and other arthropod with two body segments and eight legs |
| cnidarians | Jellyfish and coral |
| crustaceans | Arthropods with either eight or ten legs |
| echinoderms | Sea urchins and other marine animals with radial symmetry and spiny skin |
| insects | The only invertebrates that can fly |
| mollusks | Invertebrates (except for cephalopods) that rely on hard shells for protection |
| sponges | Invertebrates without symmetry, cephalization, or guts |
| worms | Long, soft-bodied animals with bilateral symmetry |
| exoskeleton | An animal that supports its body with a hard outer covering |
| endoskeleton | An animal that supports its body with an internal skeleton |
| chordates | have a notochord at some point in its life |
| Endotherms | regulate their inner temperatures using body coverings and internal process |
| Ectotherms | regulate their inner temperatures using external means |
| all animals | reproduce sexually |
| complete gut | digestive system with two openings |
| incomplete gut | digestive system with one opening |
| insects | 95% of all animals |
| Monotremes | lays eggs to reproduce |
| Marsupials | raise young in pouches |
