Haversian canals are present in :

Options

A. bone matrix
B. bone marrow
C. hyaline cartilage
D. calcified cartilage

Answer

### Step-by-Step Solution:

1. **Understanding Haversian Canals**:
- Haversian canals are microscopic tubular structures found in bones. They are essential for allowing blood vessels and nerves to pass through the bone tissue.

2. **Identifying the Structure**:
- Each Haversian canal is surrounded by concentric layers known as lamellae. This structure is crucial for the organization and function of bones.

3. **Analyzing the Options**:
- **Bone Matrix**: Haversian canals are present in the bone matrix, particularly in the outermost region of bones known as cortical bone.
- **Bone Marrow**: Bone marrow is a soft tissue found within bones that contains stem cells, but it does not contain Haversian canals.
- **Hyaline Cartilage**: This type of cartilage is found in various parts of the body (like the nose and joints) and does not have Haversian canals.
- **Calcified Cartilage**: This type of cartilage is formed by the deposition of calcium salts and also lacks Haversian canals.

4. **Conclusion**:
- Based on the analysis, Haversian canals are specifically found in the bone matrix. Therefore, the correct answer is **bone matrix**.