Enamel is principally composed of

Options

A. Calcium phosphate
B. Calcium sulphate
C. Calcicum chloride
D. Sodium phosphate

Answer

### Step-by-Step Solution:

1. **Understanding Enamel**: Enamel is the outermost layer of a tooth, which serves to protect the underlying layers, including dentin and pulp. It is the hardest substance in the human body.

2. **Composition of Enamel**: The main component of enamel is hydroxyapatite, which is a crystalline structure. Hydroxyapatite is a mineral form of calcium phosphate.

3. **Identifying the Correct Option**: The question provides four options regarding the composition of enamel:
- A) Calcium phosphate
- B) Calcium sulphate
- C) Calcium chloride
- D) Sodium phosphate

4. **Analyzing the Options**:
- **Calcium phosphate**: This is the correct answer as it is the primary component of hydroxyapatite, which makes up enamel.
- **Calcium sulphate**: This is not a component of enamel.
- **Calcium chloride**: This is also not related to the composition of enamel.
- **Sodium phosphate**: This is not the principal component of enamel.

5. **Conclusion**: Based on the analysis, the correct answer is **calcium phosphate**.

### Final Answer:
Enamel is principally composed of **calcium phosphate**.

---