Read the following features: (a) Neurogenic heart (b) Haemocoel (c) Parapodia with setae is locomotory structure (d) Double ventral nurve cord Which of the above is/are characteristic features of Nereis?

Options

A. only (a)
B. (a) and (c) only
C. (c) and (d) only
D. (a) , (c) and (d)

Answer

To determine which of the given features are characteristic of Nereis, we will analyze each feature step by step.

### Step 1: Identify the Organism
Nereis is a genus of polychaete worms, which belong to the phylum Annelida. They are commonly known as ragworms or sandworms.

### Step 2: Analyze Each Feature
1. **Neurogenic Heart**:
- Nereis has a neurogenic heart, which means that the heartbeat is controlled by the nervous system rather than by muscle contractions. This feature is characteristic of some invertebrates, including Nereis.

2. **Haemocoel**:
- Haemocoel refers to a body cavity that contains blood (hemolymph) in an open circulatory system. However, Nereis, being an annelid, has a closed circulatory system, which means it does not possess a haemocoel. Therefore, this feature is **not** characteristic of Nereis.

3. **Parapodia with Setae as Locomotory Structure**:
- Nereis has parapodia, which are lateral extensions used for locomotion and respiration. These parapodia are equipped with setae (bristle-like structures), making this feature characteristic of Nereis.

4. **Double Ventral Nerve Cord**:
- Nereis possesses a double ventral nerve cord, which is a common feature in annelids. This structure allows for coordinated movement and is characteristic of the phylum.

### Step 3: Conclusion
Based on the analysis:
- **Characteristic features of Nereis**:
- Neurogenic Heart (a)
- Parapodia with setae as locomotory structure (c)
- Double ventral nerve cord (d)
- **Not a characteristic feature**:
- Haemocoel (b)

Thus, the correct answer includes features (a), (c), and (d).

### Final Answer
The characteristic features of Nereis are (a), (c), and (d).

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