If a bone is kept in HCl, for some time, its mineral materials are dissolved and only organic matter is left behind, such a left over bone is called  

Options

A. dried bone
B. calcified bone
C. decalcified bone
D. none

Answer

To solve the question regarding what a bone is called after being kept in HCl, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Process**:
- When a bone is placed in hydrochloric acid (HCl), the mineral components of the bone, primarily calcium salts, dissolve in the acid. This process is known as decalcification.

2. **Identifying the Remaining Material**:
- After the mineral materials are dissolved, what remains is primarily the organic matter of the bone, which includes collagen and other proteins.

3. **Defining the Terms**:
- We need to understand the options provided:
- **Dried Bone**: This refers to a bone that has lost its organic matter and retains only inorganic components.
- **Calcified Bone**: This refers to a bone that has undergone the process of calcification, where calcium is deposited in the bone tissue.
- **Decalcified Bone**: This is the term used for a bone that has had its mineral content removed, leaving only the organic matrix.
- **None**: This option indicates that none of the other terms apply.

4. **Choosing the Correct Answer**:
- Since we are looking for the term that describes a bone after it has been treated with HCl, the correct answer is **Decalcified Bone**. This is because the bone has lost its mineral content and retains only the organic matter.

5. **Conclusion**:
- Therefore, the leftover bone after being kept in HCl is called **Decalcified Bone**.

### Final Answer:
The correct answer is **Decalcified Bone**.

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