Chitinous covering or perisarc is present in

Options

A. Obelia
B. Hydra
C. Aurelia
D. Physalia.

Answer

To answer the question "Chitinous covering or perisarc is present in," we can follow these steps:

### Step 1: Understand the term "Chitinous covering" or "Perisarc"
- The term "chitinous covering" refers to a protective layer made of chitin, a biopolymer that is a key structural component in the exoskeletons of arthropods and in the cell walls of fungi.
- "Perisarc" is a specific term used in the context of certain organisms, particularly in colonial organisms like hydroids.

### Step 2: Identify the organism associated with the perisarc
- The perisarc is specifically associated with the genus **Obelia**, which belongs to the class Hydrozoa within the phylum Cnidaria.
- Obelia is known for forming colonies, and its structure includes a stalk-like body that is covered by this protective layer.

### Step 3: Describe the structure of Obelia
- Obelia colonies are composed of individual polyps that are interconnected.
- The main stalk of the colony, known as the **ceno-sarc**, is covered by the perisarc, which provides protection to the colony.

### Step 4: Conclude the answer
- Therefore, the correct answer to the question is that the chitinous covering or perisarc is present in **Obelia**.

### Final Answer:
The chitinous covering or perisarc is present in **Obelia**.

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