These are considered bone - dissolving cells.

Options

A. Osteoprogenitor cells
B. Osteoclasts
C. Oscteocytes
D. Osteoblasts

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for the type of cells that are responsible for dissolving bone. This refers to the cells involved in the breakdown of bone tissue.

2. **Identifying the Options**:
- **Osteoprogenitor Cells**: These are precursor cells that develop into osteoblasts, which are involved in bone formation.
- **Osteoclasts**: These are specialized cells that break down bone tissue, thus "dissolving" it.
- **Osteocytes**: These are mature bone cells that maintain bone tissue but do not dissolve it.
- **Osteoblasts**: These are the cells responsible for bone formation, not dissolution.

3. **Analyzing Each Option**:
- **Osteoprogenitor Cells**: Not involved in bone dissolution; they are precursors to bone-forming cells.
- **Osteoclasts**: These are the cells that actively dissolve bone, making them the correct answer.
- **Osteocytes**: These maintain bone structure but do not dissolve it.
- **Osteoblasts**: These build bone, contrary to the question's requirement.

4. **Conclusion**: Based on the analysis, the cells that are considered bone-dissolving cells are osteoclasts.

**Final Answer**: Osteoclasts.

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