Annelids possess

Options

A. Cell aggreate plan
B. Blind sac plan
C. Tube within a tube plan
D. Hollow sac plan

Answer

To answer the question "Annelids possess," we need to analyze the options provided and understand the body plan of annelids.

### Step-by-Step Solution:

1. **Understanding Body Plans**: The question is asking about the body plan of annelids. Body plans refer to the structural organization of an organism.

2. **Reviewing the Options**:
- **A. Cell Aggregate Plan**: This plan is characteristic of Porifera (sponges) and involves a loose aggregation of cells. Annelids do not possess this plan.
- **B. Blind Sac Plan**: This plan is typical in organisms like cnidarians and flatworms (Platyhelminthes), where there is only one opening for both ingestion and excretion. Annelids do not have this plan.
- **C. Tube Within Tube Plan**: This plan is characterized by having two openings (mouth and anus), allowing for a complete digestive system. Annelids possess this plan as they have a well-defined digestive tract.
- **D. Holo Sac Plan**: This term is not commonly used in the classification of body plans and does not apply to annelids.

3. **Conclusion**: Based on the analysis, annelids possess the "tube within tube plan," which is option C.

### Final Answer:
Annelids possess **C. Tube within tube plan**.

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