Silk mainly consists of :-

Options

A. Keratin
B. Fibroin
C. Collagen
D. Elastin

Answer

**Step-by-Step Solution:**

1. **Understanding Silk**: Silk is a natural fiber produced by silkworms, primarily from the species Bombyx mori. It is known for its softness, luster, and strength.

2. **Identifying the Components of Silk**: Silk is primarily composed of proteins. The two main proteins found in silk are fibrin and sericin.

3. **Proportions of Proteins**: In silk, fibrin constitutes about 70-80% of the total protein content, while sericin makes up about 20-30%.

4. **Analyzing the Options**:
- **Keratin**: This is a protein found in hair, nails, and skin, but not in silk.
- **Fibrin**: This is a protein that is indeed a major component of silk.
- **Collagen**: This is a structural protein found in connective tissues, not in silk.
- **Elastin**: This protein provides elasticity to tissues, but it is not present in silk.

5. **Conclusion**: Based on the analysis, the main protein that silk consists of is fibrin.

**Final Answer**: Silk mainly consists of **fibrin**.

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