Notochord develops from

Options

A. Primary ectoderm
B. Primary endoderm
C. primary mesoderm
D. Both A and B

Answer

**Step-by-Step Solution:**

1. **Understanding the Notochord**: The notochord is a flexible rod-like structure that is crucial in the development of the vertebrate embryo. It serves as a primary axial support structure and plays a significant role in the development of the nervous system.

2. **Identifying Germ Layers**: In embryonic development, the inner cell mass differentiates into three primary germ layers: ectoderm, mesoderm, and endoderm. Each layer gives rise to different structures in the body.

3. **Role of Each Germ Layer**:
- **Ectoderm**: This layer primarily develops into the nervous system and the outer layer of the skin.
- **Endoderm**: This layer forms the gastrointestinal tract and its associated glands.
- **Mesoderm**: This layer is responsible for forming various internal structures including the heart, lungs, kidneys, gonads, blood cells, and cartilage.

4. **Specific Development of the Notochord**: The notochord specifically develops from the mesoderm. It is important to note that even though the notochord has a role in the development of the nervous system, it is derived from the mesodermal layer.

5. **Conclusion**: Based on the differentiation of the germ layers and the specific origin of the notochord, the correct answer to the question "Notochord develops from" is option C: primary mesoderm.

**Final Answer**: C) Primary mesoderm

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