Which of the following is pseudocoelomate ?

Options

A. Hydra
B. Periplaneta
C. Ascaris
D. Pheretima

Answer

To determine which of the following organisms is pseudocoelomate, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Term "Pseudocoelomate":**
- Pseudocoelomate organisms have a body cavity called a pseudocoel, which is not completely lined by mesoderm. This means that the cavity is present but does not have a true coelomic lining.

2. **Identify the Characteristics of Pseudocoelomates:**
- Pseudocoelomates typically belong to the phylum Nematoda (roundworms). They have a body cavity that is filled with fluid and is located between the endoderm and mesoderm.

3. **Review the Given Options:**
- We need to examine the options provided to see which one belongs to the phylum Nematoda. The options include:
- A. Hydra
- B. Periplaneta
- C. Ascaris
- D. Peripatus

4. **Classify Each Organism:**
- **Hydra:** Belongs to the phylum Cnidaria, which does not have a pseudocoelom.
- **Periplaneta:** This is a cockroach and belongs to the phylum Arthropoda, which has a true coelom.
- **Ascaris:** This is a roundworm and belongs to the phylum Nematoda, which is a pseudocoelomate.
- **Peripatus:** This belongs to the phylum Onychophora, which also has a true coelom.

5. **Conclusion:**
- Based on the classification, the organism that is pseudocoelomate is **C. Ascaris**.

### Final Answer:
The pseudocoelomate organism among the options is **C. Ascaris**.

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