Pick the odd pair out :-

Options

A. Cellular level: Porifera
B. Tissue level : Aschelminthes
C. Organ level : Platyhelminthes
D. Organ system level: Annelida

Answer

To solve the question "Pick the odd pair out," we will analyze each option given in the question to identify which pair does not fit with the others based on their level of organization.

### Step-by-Step Solution:

1. **Analyze Option A: Cellular Level and Porifera**
- Porifera, commonly known as sponges, are indeed characterized by a cellular level of organization. This means that their body structure is made up of a loose aggregation of cells without true tissues or organs.
- **Conclusion**: This pair is correctly matched.

2. **Analyze Option B: Tissue Level and Aesculmanthus**
- Aesculmanthus refers to a group of organisms that include roundworms, which actually have an organ system level of organization, not just a tissue level.
- **Conclusion**: This pair is incorrectly matched, making it the odd one out.

3. **Analyze Option C: Organ Level and Platyhelminthes**
- Platyhelminthes, or flatworms, possess a more complex organization than just an organ level; they have an organ system level of organization.
- **Conclusion**: This pair is incorrectly matched.

4. **Analyze Option D: Organ System Level and Annelida**
- Annelida, which includes segmented worms, is indeed characterized by an organ system level of organization.
- **Conclusion**: This pair is correctly matched.

### Final Conclusion:
Based on the analysis, the odd pair out is **Option B: Tissue Level and Aesculmanthus**, as it is incorrectly matched.