Question

Scientific name of Sea Pen/Sea Feather is
A. Pennatula
B. Gorgonia
C. Porpita
D. Velella

Answer 1

Hint: Cnidarians are diploblastic animals; they have two main cell layers, in other words, while triploblastic with three main layers are more complex animals. The two main cell layers of cnidarians from epithelia are often one cell thick and are attached to a fibrous basement membrane, which they secrete.

Complete step by step answer:
Sea pen, one of the 300 Pennatulacea species, colonial invertebrate Anthozoa marine (phylum Cnidaria). The name sea pen is due to its similarities to quill types. They happen from the polar seas to the tropics in low and deep waters.
The middle part of the animal is a peduncle, anchoring the settlement in the dust or sand, and a rachis, carrying polyps (hollow stalks, open mouth, and tentacles) or branches bearing several polyps. The middle stalk is called the main or axial polyp. The secondary polyps are those that branch out of it. Certain genera's colonies, e.g., Chunella, are very rare. Others bear up to 35,000 individuals. The mouth and tentacles of the primary polyp are degenerate and consist of only a fleshy stem reinforced by a horny central reed.
A Sea feather is called Pennatula phosphorea by the scientific name. The feather is so-called because it has a stalk and a 'rachis,' with branches on appendices.
Gorgonia is known by the name Venus sea fan.
Porpita’s scientific name is Medusa porpita.
Velella’s scientific name is wind sailor.

Therefore, option A 'Pennatula' is the right answer.

Note: Sea stalks may deflate or expand through the interconnecting hollow canals of polyps by exporting or taking in water in cnidarians. At the end of each polyp, they feed on tiny bodies trapped by tentacles. When touched or otherwise stimulated, most sea types are luminescent or luminescent.