Question

Pennatula and Gorgonia are
A) Hydrozoans
B) Scyphozoans
C) Corals
D) Ctenophores

Answer 1

Hint: Cnidaria is a phylum of kingdom Animalia containing thousands of species of aquatic animals. They are found in both freshwater and marine water environments. Pennatula and Gorogonia belong to Cnidaria.

Complete answer:
Cnidaria have the presence of special cells called cnidocytes that help them in capturing the prey. Their body also consists of a jelly like substance called mesoglea and this is found between two layers of epithelium. Cnidarians are basically divided into four groups namely groups: wholly sessile Anthozoa (sea anemones, Pennatula, Gorgonia); swimming Scyphozoa (jellyfish); Cubozoa (box jellies); and Hydrozoa (a diverse group).

Let us analyze the options to find out the correct answer.

Option A: Hydrozoans are small predatory animals which might live alone or in colonies. They usually live in saltwater. Those living inside the colony usually cannot live outside the colony.Therefore, this is the incorrect option.

Option B: Scyphozoa is a group of animals that belongs to the phylum Cnidraia and in the group swimming Scyphozoa. They are commonly called jellyfish.Therefore, this is the incorrect option.

Option C: Corals is an underwater ecosystem that consists of Cnidarians like Pennatula and Gorgonia. They belong to the class of Anthozoa of the phylum Cnidaria. Therefore, this is the correct option.

Option D: Ctenophores are those organisms that belong to the phylum of invertebrates. They live in marine water worldwide. They use their cilia for swimming. Interestingly, they are the largest animals who can swim using their cilia.Therefore, this is the incorrect option.

Thus, the correct answer is option (C) Corals.

Note:
i) Pennatula is also called Sea Pen or Sea Feather and Gorgonia is commonly called Sea Fan.
ii) The size range of the animals in corals can be 1mm to 10m, however they may seem larger as most of them live in colonies.