Which of the following is a protein?

Options

A. Glycogen
B. Amylopectin
C. Keratin
D. Lecithin.

Answer

To determine which of the given options is a protein, we need to analyze each option based on its definition and characteristics.

### Step-by-Step Solution:

1. **Identify the Options**: We have four options to consider: Glycogen, Amylopectin, Keratin, and one unspecified option.

2. **Analyze Glycogen**:
- Glycogen is a polysaccharide that serves as a form of energy storage in animals.
- It is composed of glucose units linked together.
- **Conclusion**: Glycogen is not a protein.

3. **Analyze Amylopectin**:
- Amylopectin is a component of starch, which is also a polysaccharide.
- It consists of glucose units and is primarily found in plants.
- **Conclusion**: Amylopectin is not a protein.

4. **Analyze Keratin**:
- Keratin is a type of fibrous protein.
- It is found in various structures such as hair, nails, and feathers.
- **Conclusion**: Keratin is indeed a protein.

5. **Final Decision**:
- Based on the analysis, the only protein among the options is Keratin.

### Answer:
**Keratin is the protein among the given options.**

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