Question

Which One of the following animals is Triploblastic?
A) Sponges
B) Jellyfish
C) Hydra
D) Flatworms

Answer 1

Hint: The term Blastic is referred to cells present in the body. Triploblastic organisms have three germ layers and they develop through embryonic development. All organisms are triploblastic except the ones belonging to Porifera and coelenterates.

Complete answer:
The body tissue of Triploblastic organisms contains three Germ layers Ectoderm, Endoderm, mesoderm. Triploblasty is a condition of the gastrula, where three germ layers are formed. The higher and intermediate animals develop from a triploblastic embryo.

Let us analyze the given options:
A) SPONGES: Sponges are Aquatic invertebrate animals that have double-walled bodies with loosely aggregated cells. They belong to the phylum Porifera. They are found in the oceans, seas, and rivers. Sponges are Diploblastic. They are mainly asymmetrical and some show radial symmetry.
B) JELLYFISH: Jellyfish are free-swimming marine Invertebrate animals from the phylum Cnidaria. They are made up of smooth bag-like bodies and tentacles armed with tiny, stinging cells. Jellyfish belong to Diploblastic animals.
C) HYDRA: Hydra belongs to diploblastic animals from the phylum Cnidaria. They are small freshwater organisms. Hydra has tiny, tube-shaped bodies that contain several tentacles on one end. They have the regenerative ability. Hydra is mostly found in temperate and tropical regions.
D) FLATWORMS: These are the members of the phylum Platyhelminths. Flatworms are free-living, bilateral, unsegmented, soft-bodied invertebrates and they are found in freshwater, ponds, lakes. Flatworms are triploblastic organisms. They are made up of three germ layers in embryo development.

Thus, the correct answer is FLATWORMS (D).

Note: Triploblastic animals contain three layers: Endoderm, Ectoderm and mesoderm. Endoderm includes lungs, stomach, colon, liver, urinary bladder. An ectoderm forms epidermis, blood, eye lens, brain, spinal cord. Mesoderm leads to the production of true organs, muscle types, bone, connective tissue, circulatory system. In diploblastic animals Endoderm and Ectoderm layers are present and the mesoderm layer is absent.