Identify animals that are NOT triploblastic.

The correct answer is Coelenterates

Key Points:Triploblastic animals

• Triploblastic animals create the endoderm, ectoderm, and mesoderm, the three basic germ layers.
• True organs, different muscle types, bone, connective tissue, the circulatory system, the notochord, and other structures can be produced by the mesoderm.
• Animal endoderm that is triploblastic includes the lungs, stomach, colon, liver, urinary bladder, etc.
• Ectoderm produces the epidermis, lens of the eye, brain, spinal cord, and other tissues.
• The triploblastic creatures are bilaterally symmetrical.
• When compared to diploblastic animals, triploblastic animals are much more diversified.
• Animals like Platyhelminthes, annelids, arthropods, mollusks, echinoderms, and chordates are examples of triploblastic organisms.

Platyhelminthes:

• ​The flatworms, also known as Platyhelminthes, are a group of soft-bodied, generally basic bilaterian, unsegmented invertebrates.

Echinodermata:

• ​Any member of phylum Echinodermata is an echinoderm.
• The adult sea lilies, also known as the "stone lilies," brittle stars, starfish, sea urchins, sand dollars, and sea cucumbers are distinguishable by their (often five-point) radial symmetry.

Chordata: 

• ​An animal belonging to the phylum Chordata is a chordate.
• Five synapomorphies, or basic physical traits, that set chordates apart from all the other taxa are present in all chordates at some point during their larval or adult stages.