Which one is incorporated in muscle fibres? 

Options

A. Acetylcholine
B. Myoglobin
C. Histone
D. Cytochrome

Explanation

**Step-by-Step Solution:**

1. **Understanding Muscle Fibers**: Muscle fibers are specialized cells that make up muscle tissue. They are responsible for contraction and movement in the body.

2. **Identifying Key Components**: Within muscle fibers, there are various proteins and organelles that play crucial roles in their function. One important aspect of muscle fibers is their ability to utilize oxygen for energy production.

3. **Oxygen-Carrying Protein**: The primary oxygen-carrying protein found in muscle fibers is called myoglobin. Myoglobin is similar to hemoglobin, which is found in red blood cells, but it is specifically adapted for muscle tissue.

4. **Function of Myoglobin**: Myoglobin binds to oxygen molecules and facilitates their transport from the bloodstream (carried by red blood cells) to the mitochondria within muscle cells. Mitochondria are the powerhouses of the cell where cellular respiration occurs, producing ATP (adenosine triphosphate), the energy currency of the cell.

5. **Conclusion**: Therefore, the correct answer to the question "Which one is incorporated in muscle fibers?" is myoglobin.

**Final Answer**: Myoglobin is incorporated in muscle fibers.

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