Which of the following is pseudocoelomate animal

Options

A. Whip-worm
B. Sand-worm
C. Flat - worm
D. Earth worm

Answer

To determine which of the given options is a pseudocoelomate animal, we can follow these steps:

### Step 1: Understand the Definition of Coelom
- A coelom is a body cavity that is present between the body wall and the gut, and it is lined by mesoderm. Organisms that possess a true coelom are called coelomates.

### Step 2: Identify Types of Body Cavities
- **Coelomates**: Organisms with a true coelom (e.g., Phylum Annelida, Mollusca, Arthropoda, Echinodermata, Hemichordates, and Chordates).
- **Pseudocoelomates**: Organisms where the body cavity is not a true coelom but is instead a pseudocoel, which is a fluid-filled cavity lined by mesoderm on one side and endoderm on the other. These organisms belong to the Phylum Nematoda (roundworms).
- **Acoelomates**: Organisms that lack a body cavity altogether (e.g., Phylum Platyhelminthes or flatworms).

### Step 3: Analyze the Given Options
- **A. Whipworm**: This is a type of roundworm (Phylum Nematoda), which is a pseudocoelomate.
- **B. Sandworm**: This belongs to Phylum Annelida, which are coelomates.
- **C. Flatworm**: This belongs to Phylum Platyhelminthes, which are acoelomates.
- **D. Earthworm**: This also belongs to Phylum Annelida, which are coelomates.

### Step 4: Conclusion
- From the analysis, the only pseudocoelomate animal among the options is the **Whipworm (A)**.

### Final Answer
- The pseudocoelomate animal is **A. Whipworm**.

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