mollusk
It is invertebrate .
Invertebrate
no, a sea cucumber is an Echinoderm.
The sea cucumber belongs to the same animal group as the starfish, the echinoderms.
The Sea Cucumber is a soft-bodied invertebrate that is related to the starfish and sea urchins. There are over 1100 species that are found worldwide in intertidal zones as well as deep waters.
mollusk
Echinodermata
Echinodermata
Because the scientists believed it looked like a cucumber and it was under the sea so therefore, a sea cucumber has derived from cucumber-like look.
No a sea cucumber does not have a brain.
no a sea cucumber does not have a backbone.
A sea urchin is an invertebrate.