In the center of I-Band, is an elastic fiber, which bisect it

Answer

**Step-by-Step Solution:**

1. **Understanding Myofibrils**: Each myofibril, which is a structural unit of a muscle cell, consists of alternating dark and light bands. These bands are crucial for muscle contraction and relaxation.

2. **Identifying the Bands**: The light bands are referred to as I bands (isotropic bands) because they appear lighter under a microscope. The dark bands are called A bands (anisotropic bands) as they appear darker.

3. **Location of the Z Line**: In the center of each I band, there is a structure known as the Z line (or Z band). This line is an elastic fiber that bisects the I band.

4. **Attachment of Filaments**: The thin filaments, which are primarily made of actin, are firmly attached to the Z line. This attachment is essential for the muscle contraction process.

5. **Conclusion**: Therefore, the elastic fiber that bisects the I band is known as the Z line.

**Final Answer**: The elastic fiber that bisects the I band is called the Z line.

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