The structural and functional unit of the striated muscle fibre is called ……………..

Explanation

**Step-by-Step Text Solution:**

1. **Understanding Muscle Fiber**: Striated muscle fibers are a type of muscle tissue that is characterized by a striped appearance under a microscope. They are responsible for voluntary movements in the body.

2. **Identifying the Unit**: The question asks for the structural and functional unit of the striated muscle fiber. In muscle physiology, the basic unit that allows for contraction and relaxation is crucial to understand.

3. **Defining the Sarcomere**: The sarcomere is defined as the basic contractile unit of striated muscle fibers. It is the segment of the muscle fiber that is responsible for muscle contraction.

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