To solve the question regarding the modified stem that grows vertically to the soil surface, bears nodes, internodes, buds, and scaly leaves, we can follow these steps:
### Step-by-Step Solution:
1. **Understand the Question**: The question asks for a modified stem that grows vertically, has nodes, internodes, buds, and scaly leaves.
2. **Analyze the Options**: We need to evaluate the provided options to find which one fits the description.
3. **Option 1: Bulb**:
- A bulb has a reduced stem and a disc-like structure that surrounds fleshy scaly leaves.
- Example: Onion.
- Characteristics: It does not primarily grow vertically above the soil surface; instead, it is more of a storage organ with roots growing from the base.
- Conclusion: This does not match the description.
4. **Option 2: Corm**:
- A corm is a condensed stem modification that grows vertically under the soil surface.
- It has spherical nodes and internodes and can have contractile roots.
- Examples: Colocasia, Alocasia.
- Conclusion: This matches the description of growing vertically and having nodes, internodes, and scaly leaves.
5. **Option 3: Tuber**:
- A tuber is an underground stem that becomes swollen and has "eyes" (axillary buds).
- Example: Potato.
- Characteristics: While it has buds, it does not have distinct nodes and internodes as described.
- Conclusion: This does not match the description.
6. **Option 4: Rhizome**:
- A rhizome is a fleshy, horizontal stem found underground.
- It has nodes and internodes but grows horizontally, not vertically.
- Conclusion: This does not match the description.
7. **Final Conclusion**: After analyzing all options, the correct answer is **Corm** (Option 2) because it grows vertically, has nodes, internodes, buds, and scaly leaves.
### Final Answer:
The modified stem which grows vertically to the soil surface, bears nodes, internodes, buds, and scaly leaves is **Corm**.
