Spongy bone lacks :

Options

A. Lamellae
B. Lacunae
C. Osteocytes
D. Osteons

Answer

### Step-by-Step Solution

1. **Understanding Spongy Bone**: Spongy bone, also known as cancellous bone, is a type of bone tissue that is lighter and less dense than compact bone. It has a porous structure, which is essential for its function.

2. **Identifying Key Components**: The primary components of bone tissue include osteons, osteocytes, lacunae, and lamellae. Osteons are the structural units of compact bone, while spongy bone has a different structure.

3. **Absence of Osteons**: The key characteristic of spongy bone is that it lacks osteons. Instead of being organized into osteons, spongy bone consists of trabeculae, which are plate-like structures.

4. **Structure of Trabeculae**: Trabeculae are made up of lamellae arranged in a plate-like formation. This structure allows spongy bone to maintain strength while being lighter than compact bone.

5. **Presence of Bone Marrow**: Between the trabeculae, red bone marrow is found. This marrow is important for the production of blood cells.

6. **Function of Blood Vessels**: Blood vessels are present within the spongy bone, and they serve two main functions: delivering nutrients to the osteocytes and removing waste products.

7. **Conclusion**: Therefore, the correct answer to the question "Spongy bone lacks:" is **osteons**.