The unique characteristic of phylum annelida is

Options

A. coleom
B. nephridia
C. hermaphrodite
D. alimentary canal is complete

Answer

To answer the question regarding the unique characteristic of phylum Annelida, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Phylum Annelida**:
- Annelida is a phylum that includes segmented worms such as earthworms, leeches, and polychaetes.

2. **Identifying the Options**:
- The options provided are:
- A) Coelom
- B) Nephridia
- C) Hermaphrodite
- D) Complete Alimentary Canal

3. **Evaluating Each Option**:
- **Coelom**:
- While Annelida has a true coelom (body cavity), many other phyla also possess coeloms (e.g., Arthropoda, Mollusca). Therefore, this is not unique to Annelida.
- **Nephridia**:
- Nephridia are specialized excretory organs found in Annelids. They are segmentally arranged coiled tubules and are crucial for osmoregulation and excretion. This characteristic is unique to Annelida.
- **Hermaphrodite**:
- Hermaphroditism (having both male and female reproductive organs) is found in many animal phyla, not just Annelida. Thus, this is not unique.
- **Complete Alimentary Canal**:
- A complete alimentary canal is also present in other phyla, such as Platyhelminthes and Nematoda, making it not unique to Annelida.

4. **Conclusion**:
- After evaluating all the options, the unique characteristic of phylum Annelida is the presence of **nephridia**.

### Final Answer:
The unique characteristic of phylum Annelida is the presence of **nephridia**.

---