Identify the phylum associated with the presence of false coelom.

Options

A. Platyhelminthes
B. Cnidaria
C. Annelida
D. Nematoda

Answer

**Step-by-Step Solution:**

1. **Understanding Coelom Types**:
- Coelom is a fluid-filled body cavity that is found in many animals. It can be classified into three types: true coelom, pseudocoelom (false coelom), and acoelom.
- A true coelom is completely lined by mesoderm, while a pseudocoelom is only partially lined by mesoderm.

2. **Identifying Pseudocoelom**:
- Pseudocoelom (or false coelom) is a body cavity that is found between the mesoderm and the endoderm. It is not completely surrounded by mesodermal tissue.

3. **Phylum with Pseudocoelom**:
- The phylum that is primarily associated with the presence of a pseudocoelom is **Nematoda** (also known as roundworms).
- Organisms in this phylum have a pseudocoelomic body structure, which distinguishes them from other phyla.

4. **Exclusion of Other Phyla**:
- Other phyla such as Platyhelminthes (flatworms) do not possess a pseudocoelom; they are acoelomate (without a body cavity).
- Annelida (segmented worms) possess a true coelom, hence they are coelomate animals.

5. **Conclusion**:
- Therefore, the phylum associated with the presence of a false coelom is **Nematoda**.

**Final Answer**: The phylum associated with the presence of false coelom is **Nematoda**.

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