Identify the phylum without tissue level organization.

Options

A. Cnidaria
B. Nematoda
C. Porifera
D. None of these

Answer

**Step-by-Step Solution:**

1. **Understand the Question**: The question asks for a phylum that lacks tissue-level organization. This means we are looking for a group of organisms that are organized at the cellular level only, without the formation of tissues.

2. **Review the Options**: The options provided include various phyla. We need to analyze each option to determine if they have tissue-level organization or not.

3. **Analyze Phylum Cnidaria**: Cnidaria includes organisms like jellyfish and corals. They exhibit tissue-level organization, as they have specialized cells that form tissues. Therefore, Cnidaria is not the correct answer.

4. **Analyze Nematoda**: Nematodes, or roundworms, belong to the phylum Nematoda. They have a more advanced organization with organ systems, indicating that they also do not fit the criteria of lacking tissue-level organization.

5. **Analyze Phylum Porifera**: Porifera, commonly known as sponges, are characterized by their cellular-level organization. They do not have true tissues; instead, their bodies are made up of various types of cells, such as choanocytes and amoebocytes, which perform different functions. This phylum is known for having a water canal system, which is a characteristic feature of sponges.

6. **Conclusion**: Based on the analysis, the phylum that lacks tissue-level organization is Porifera.

7. **Final Answer**: Porifera

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