The only incorrectly matched pair is

Options

A. Phylum-Porifera, Level of organisation-Cellular level
B. Phylum- Cnidaria, Level of organisation-Tissue level
C. Phylum- Annelida, Level of organisation- Organ level only
D. Phylum- Mollusca, Level of organisation-Organ-system level

Explanation

To determine the only incorrectly matched pair regarding the phyla and their levels of organization, we will analyze each phylum and its corresponding level of organization step by step.

### Step 1: Identify the Phylum Porifera
- **Phylum**: Porifera
- **Level of Organization**: Cellular level
- **Explanation**: Porifera, commonly known as sponges, exhibit a cellular level of organization. They do not have true tissues or organs, making this match correct.

### Step 2: Identify the Phylum Cnidaria
- **Phylum**: Cnidaria
- **Level of Organization**: Tissue level
- **Explanation**: Cnidarians, such as jellyfish and corals, have a tissue level of organization. This means they have specialized cells grouped into tissues, which is also a correct match.

### Step 3: Identify the Phylum Annelida
- **Phylum**: Annelida
- **Level of Organization**: Organ level
- **Explanation**: Annelids, like earthworms, have a well-developed organ system. They possess true organs and organ systems, indicating a higher level of organization. However, the video mentions that they have both tissue and organ systems, which suggests that the description might be misleading.

### Step 4: Identify the Phylum Mollusca
- **Phylum**: Mollusca
- **Level of Organization**: Organ system level
- **Explanation**: Mollusks, such as snails and octopuses, have a complex organ system. They possess well-developed organs and organ systems, making this match correct.

### Conclusion
After analyzing the phyla and their levels of organization:
- The only incorrectly matched pair is **Annelida** with the description of only having an **organ level**. In reality, Annelids possess both tissue and organ systems, indicating a more complex level of organization.

### Summary of Incorrect Match
- **Incorrect Match**: Annelida - Organ Level (should be Organ System Level)