The structural protein found in animals is

Options

A. keratin
B. collagen
C. albumin
D. thrombin

Answer

To answer the question regarding the structural protein found in animals, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Options**: The question provides four options:
- Keratin
- Collagen
- Albumin
- Thrombin

2. **Analyze Each Option**:
- **Keratin**: This is a structural protein found in hair, nails, and the outer layer of skin. It provides strength and protection.
- **Collagen**: This is a fibrous protein that is the most abundant in the animal kingdom. It forms a significant part of connective tissues such as tendons, ligaments, and skin.
- **Albumin**: This is a protein found in blood plasma that helps maintain osmotic pressure and transport substances.
- **Thrombin**: This is an enzyme involved in blood clotting.

3. **Determine the Structural Role**: The question specifically asks for a structural protein. Keratin and collagen are both structural proteins, but collagen is known to be the most abundant and plays a crucial role in the structure of connective tissues in the body.

4. **Conclusion**: Based on the analysis, the correct answer is **Collagen**, as it is the primary structural protein in animals and is essential for maintaining the integrity and strength of various tissues.

### Final Answer:
The structural protein found in animals is **Collagen**.

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