Which of the following class of arthropoda has cephalothorax ?

Options

A. Crustacea
B. Chilopoda
C. Diplopoda
D. Insecta

Answer

To determine which class of Arthropoda has a cephalothorax, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Term Cephalothorax**:
- Cephalothorax refers to a body structure where the head and thorax are fused together, meaning there is no distinct separation between these two regions.

2. **Identify Classes of Arthropoda**:
- The major classes of Arthropoda include:
- Crustacea
- Chilopoda
- Diplopoda
- Insecta
- Arachnida
- Merostomata

3. **Analyze Each Class**:
- **Crustacea**: This class includes crabs, lobsters, and prawns. In these organisms, the head and thorax are fused, forming a cephalothorax.
- **Chilopoda**: This class includes centipedes. They have a clearly defined head, thorax, and abdomen, so they do not have a cephalothorax.
- **Diplopoda**: This class includes millipedes. Similar to Chilopoda, they have distinct body segments and do not possess a cephalothorax.
- **Insecta**: This class includes insects like cockroaches, which also have a clearly defined head, thorax, and abdomen.
- **Arachnida**: This class includes spiders and ticks, which have a distinct separation of head and thorax.
- **Merostomata**: This class includes horseshoe crabs. They also have a cephalothorax, as their head and thorax are fused.

4. **Conclusion**:
- The classes that possess a cephalothorax are **Crustacea** and **Merostomata**. However, since the question asks for the class that is most commonly known for having a cephalothorax, the answer is **Crustacea**.

### Final Answer:
The class of Arthropoda that has a cephalothorax is **Crustacea**.

---