What do you mean by striations of muscle fiber?

Explanation

### Step-by-Step Solution:

1. **Definition of Striations**: Striations in muscle fibers refer to the alternating light and dark bands that are visible under a microscope. These bands give skeletal and cardiac muscles their characteristic striped appearance.

2. **Location of Striations**: Striations are primarily found in two types of muscle tissue: skeletal muscle and cardiac muscle. These muscles are responsible for voluntary and involuntary movements, respectively.

3. **Formation of Striations**: The striated appearance is due to the arrangement of proteins within the muscle fibers. The proteins involved are primarily actin and myosin, which are essential for muscle contraction.

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