Bone should be regarded as :

Options

A. Metabolically dynamic structure
B. Homeostatic reservoir of ions
C. Exchange centre for `Ca^(++)` between bone and blood
D. All of these

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks how to regard bone, implying that we need to evaluate the characteristics or functions of bone based on the provided options.

2. **Analyzing the Options**:
- **Option 1: Metabolic dynamic structure**: Bones are not static; they are living tissues that undergo constant remodeling and changes. This indicates that bones are indeed metabolic dynamic structures.
- **Option 2: Homeostatic reservoir of ions**: Bones store essential minerals, particularly calcium and phosphorus, which are crucial for maintaining homeostasis in the body. Therefore, this statement is also correct.
- **Option 3: Exchange center for calcium ions**: Bones play a significant role in the exchange of calcium ions between the bone and the bloodstream, which is vital for various physiological processes. This statement is also accurate.
- **Option 4: All of these**: Since all the previous statements are correct, this option encompasses all the correct characteristics of bone.

3. **Choosing the Correct Answer**: Given that all the individual statements about bones are correct, the most comprehensive answer is **Option 4: All of these**.

4. **Conclusion**: Therefore, bone should be regarded as a metabolic dynamic structure, a homeostatic reservoir of ions, and an exchange center for calcium ions, making the best choice Option 4.

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