Which embryonic structure is replaced by vertebral column in frog ?

Options

A. Neural canal
B. Archenteron
C. Notochord
D. Blastocoel

Answer

To answer the question "Which embryonic structure is replaced by the vertebral column in frogs?", we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Phylum**: Frogs belong to the phylum Chordata, specifically to the subphylum Vertebrata. One of the key characteristics of Chordates is the presence of a notochord during some stage of their development.

2. **Identifying the Notochord**: The notochord is a flexible rod-like structure located on the dorsal side of the embryo. It serves as a skeletal structure in the early stages of development.

3. **Developmental Changes**: In vertebrates, including frogs, the notochord is not retained in its original form in the adult organism. Instead, it undergoes a transformation.

4. **Formation of the Vertebral Column**: During the development of vertebrates, the notochord is replaced by the vertebral column (spine). This transformation provides a more complex and rigid structure for support and protection of the spinal cord.

5. **Conclusion**: Therefore, the embryonic structure that is replaced by the vertebral column in frogs is the notochord.

### Final Answer:
The embryonic structure replaced by the vertebral column in frogs is the **notochord**.

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