Question

Diploblastic animals occur in.
A. Annelida
B. Platyhelminthes
C. Coelenterata
D. None of these

Answer 1

Hint: Diploblastic animals have such a blastula that includes ctenophora and Cnidaria. The jellyfish, comb jellies, and sea anemones are diploblastic in nature.

Complete answer:
To solve this question, we should first understand the meaning of diploblastic. The organisms that have ctenophora and Cnidaria are the diploblastic animals. They are called diploblastic because of the presence of two germ layers; endoderm and ectoderm. The diploblastic animals do not develop true organs due to the absence of mesoderm On the other hand the triploblastic structure developed in higher and intermediate animals. They have three germ layer ectoderm, endoderm, and mesoderm; the mesoderm is developed in between the other two layers because of the presence of this third layer triploblastic animals can develop true organs. The diploblastic animals include the jellyfish, sea anemones, etc that match this characteristic. The animals of phylum coelenterata are diploblastic in nature.
Now lets us find the solution from the given options:
Annelida is the phylum that includes the worms. They have a segmented body that is bilaterally symmetrical; they are triploblastic, invertebrate organisms. They have a mesoderm germ layer along with endoderm and ectoderm.
Now, Platyhelminthes is the phylum that includes flatworm. They are bilaterally symmetrical and triploblastic and have three layers of germ cells.
The Coelenterata is a phylum that radially symmetrical body forms and is diploblastic in nature. They have no coelom. They have two germ layer endoderm and ectoderm.

Thus, the right answer is option C. i.e., Coelenterata.

Note: The animals of phylum Coelenterata have no coelom. They have only one opening in the body. They have sensory tentacles formed from nematocysts or colloblasts to capture the prey, especially planktonic.