Name the main constituents of bone mass.

Explanation

### Step-by-Step Solution:

1. **Understanding Bone Composition**: Bone is classified as a heterogeneous composite material, meaning it is made up of different components that contribute to its structure and function.

2. **Identifying the Main Constituents**:
- **Mineral Phase**: The primary mineral component of bone is hydroxyapatite. This mineral provides strength and rigidity to the bone structure.
- **Organic Phase**: The organic component of bone consists mainly of collagen and other proteins. Specifically:
- About 90% of the organic phase is collagen, which is crucial for providing flexibility and tensile strength.
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