Question

In one of her expeditions, a marine biologist finds a new organism that has an unsegmented, radially-symmetrical body with spiny skin. Under which phylum should she classify this organism?

Annelids
Arthropods
Echinoderms
Mollusks

Answer 1

I believe the answer is Echinoderms. 

Answer 2

Answer: Echinoderms

Echinoderms are the marine invertebrate organisms. These includes starfishes, sea urchins and sea cucumbers. These are found in the ocean depth, intertidal zone and abyssal zone. They exhibit radial symmetry, unsegmented body, calcareous skeleton and some of them also exhibit spines to keep them protected from being eaten by the predators.