One characteristic of the class Holothuroidea is that they:

A) are predators that consume partially digested prey.
B) are mostly extinct species.
C) have a reduced endoskeleton consisting of microscopic plates embedded in the body wall.
D) have movable spines that are used to facilitate locomotion.
E) have a distinct central disk with very long, slender arms.

Microscopic Plates

Tiny, often mineralized structures observable under a microscope, which can be part of the skeletal system of some organisms.

Holothuroidea

A class of marine invertebrates within the phylum Echinodermata, commonly known as sea cucumbers.

Endoskeleton

An internal support structure of an organism, typical of vertebrates, providing physical support and protection for the body.