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 has a porous structure. It is found at the ends of long bones and in the interior of others, providing strength and support while being lighter than compact bone.

2. **Identifying the Options**:
- The question asks what is lacking in spongy bone from the given options. The options provided are:
- A) Lamellae
- B) Lacunae
- C) Osteocytes
- D) Osteon

3. **Evaluating Each Option**:
- **Option A: Lamellae** - Lamellae are thin layers of bone matrix. They are present in spongy bone, so this option is incorrect.
- **Option B: Lacunae** - Lacunae are small cavities in bone that contain osteocytes. They are also present in spongy bone, so this option is incorrect.
- **Option C: Osteocytes** - Osteocytes are mature bone cells located within the lacunae. They are found in spongy bone, making this option incorrect as well.
- **Option D: Osteon** - Osteons, or Haversian systems, are the structural units of compact bone. They are not found in spongy bone, making this the correct answer.

4. **Conclusion**:
- The correct answer is **D) Osteon**, as spongy bone lacks osteons.