Question

Which of the following organism is not triploblastic?

• A. Worms
• B. Arthropods
• C. Molluscs
• D. Jellyfish

Answer 1

The correct option is D

Jellyfish

The correct option is D.

Explanation of correct option:

1. Those animals in which the developing embryo has a third germinal layer, mesoderm, in between the ectoderm and endoderm, are called triploblastic animals.
2. Animals of phylum Platyhelminthes to Chordata are triploblastic.
3. Animals in which the cells are arranged in two embryonic layers, external ectoderm, and internal endoderm, are called diploblastic animals.
4. Jellyfish belongs to the phylum Coelenterata, and it is a diploblastic animal.

Explanation of incorrect options:

Option A: Worms belong to the phylum Annelida. They are triploblastic animals.

Option B: Arthropods are triploblastic animals.

Option D: Molluscs are triploblastic animals.

Final answer: Jellyfish organism is not triploblastic.