Question

Starfish belongs to phylum of
A) Porifera
B) Coelenterata
C) Echinodermata
D) Arthropoda

Answer 1

Hint: Starfishes are exclusively marine and are one of the widely distributed marine animals. They are triploblastic and have spiny skin as a characteristic feature. None of the species is found in freshwater to date.

Complete answer:
Starfish Classification
Kingdom- Animalia
Phylum- Echinodermata
Class- Asteroidea
Order- Forcipulatida
Genus- Asterias
Key points regarding Phylum Echinodermata are as follows-
• The echinoderms are marine and among the most common and widely distributed marine animals.
• They occur in all seas.
• They have radial symmetry.
• They are triploblastic, coelomate, without a definite head but distinct oral and arboreal surfaces.
• Body shape is rounded to cylindrical or star-like.
• Body wall consists of an outer epidermis, middle dermis, and peritoneum.
• There is a presence of a water vascular or ambulacral system.
• Circulatory or lunar system is typically present.
• Nervous system is primitive.
• Respiration occurs through different structures according to the type of organism. Eg- Papulae in starfishes.
• Sense organs are poorly developed.
• Sexes are separate with few exceptions.
Starfishes or Asterias belong to Echinodermata as they follow the characteristics of the phylum.
Let’s have a look at other options.
Porifera includes the sponges.
Coelenterata includes the multicellular organisms with hollow intestines. Eg- Hydra.
Arthropoda includes the insects with jointed appendages.

Starfish belongs to the phylum Echinodermata. The correct option is (C).

Additional information: The body of starfish is star-shaped consisting of a central disc with five radiating arms that are broad at base tapering towards the external side.

Note: The phylum Echinodermata, as mentioned above is purely marine.
So, if the habitat of an organism is known then the phylum of that organism becomes easy to determine.
For example- The starfishes are purely marine and also all the organisms in Echinodermata are exclusively marine.
The water vascular system is found in starfish.