What is true about Nereis, scorpion, cockroach and silver fish?
(a) They all belong to the same phylum .
(b) They all have jointed paired appendages .
(c) They all possess dorsal heart.
(d) None of them is aquatic

Options

A. They all belong to the same phylum .
B. They all have jointed paired appendages .
C. They all possess dorsal heart.
D. None of them is aquatic

Answer

To determine what is true about Nereis, scorpion, cockroach, and silverfish, let's analyze each option step by step.

### Step 1: Identify the Phylum of Each Organism
- **Nereis**: This organism belongs to the phylum **Annelida** (segmented worms).
- **Scorpion**: This organism belongs to the phylum **Arthropoda** (jointed-legged invertebrates).
- **Cockroach**: This organism also belongs to the phylum **Arthropoda**.
- **Silverfish**: This organism belongs to the phylum **Arthropoda** as well.

### Step 2: Evaluate Option (a)
- **Option (a)** states that they all belong to the same phylum. Since Nereis belongs to Annelida and the others belong to Arthropoda, this statement is **false**.

### Step 3: Evaluate Option (b)
- **Option (b)** states that they all have jointed paired appendages. While scorpions, cockroaches, and silverfish have jointed appendages, Nereis does not have jointed appendages as it is an annelid. Therefore, this statement is also **false**.

### Step 4: Evaluate Option (c)
- **Option (c)** states that they all possess a dorsal heart. In fact, all these organisms have a dorsal heart. Nereis, being an annelid, has a dorsal vessel that functions similarly to a heart, while scorpions, cockroaches, and silverfish (all arthropods) have a dorsal heart as well. Thus, this statement is **true**.

### Step 5: Evaluate Option (d)
- **Option (d)** states that none of them is aquatic. Nereis is aquatic, living in marine environments. Therefore, this statement is **false**.

### Conclusion
The correct answer is **(c)**: They all possess a dorsal heart.

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