Is a sea cucumber a sponge?

No, a sea cucumber is not a sponge. Sea cucumbers are marine animals belonging to the echinoderm phylum, which also includes starfish and sea urchins. They have a soft, elongated body and are part of the animal kingdom, while sponges are simple, multicellular organisms classified under the phylum Porifera. The two groups differ significantly in structure, function, and Biology.