Brain and spinal cord of vertebrates have been derived from

Options

A. Dorsal hollow nerve cord
B. Ventral solid nerve cord
C. Lateral nerve cord
D. Dorsal solid nerve cord

Answer

To answer the question regarding the origin of the brain and spinal cord in vertebrates, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Structure of Chordates**:
- All chordates, including vertebrates, share certain key features during their embryonic development. One of these features is the presence of a nerve cord.

2. **Identifying the Type of Nerve Cord**:
- In chordates, the nerve cord is characterized as a **dorsal hollow nerve cord**. This is a unique embryonic structure that differentiates chordates from other animal phyla.

3. **Formation of the Central Nervous System**:
- The dorsal hollow nerve cord develops into the central nervous system (CNS) as the organism matures. The CNS comprises the brain and spinal cord, which are crucial for coordinating bodily functions.

4. **Evaluating Other Options**:
- **Ventral solid nerve cord**: This type of nerve cord is found in invertebrates and is not applicable to vertebrates.
- **Lateral nerve cord**: This is not a characteristic of chordates and is associated with specific structures in other animal groups.
- **Dorsal solid nerve cord**: This is found in annelids and arthropods, and it is not hollow, making it incorrect for vertebrates.

5. **Conclusion**:
- Based on the above analysis, the correct answer is that the brain and spinal cord of vertebrates are derived from the **dorsal hollow nerve cord**.

### Final Answer:
The brain and spinal cord of vertebrates have been derived from the **dorsal hollow nerve cord**.

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