H-zone of striated muscle fibre represents both thick and thin filaments.

Answer

**Step-by-Step Solution:**

1. **Understanding the Structure of Muscle Fibers**:
- Muscle fibers are composed of units called sarcomeres. Each sarcomere contains thick and thin filaments that are responsible for muscle contraction.

2. **Identifying the Components**:
- The thick filaments are primarily made up of myosin, while the thin filaments are primarily made up of actin.

3. **Locating the H-zone**:
- Within a sarcomere, the H-zone is the region that is located in the center of the A-band (which contains both thick and thin filaments).

4. **Analyzing the H-zone**:
- The H-zone specifically represents only the thick filaments (myosin) and does not include any thin filaments (actin).

5. **Conclusion**:
- Therefore, the statement "H-zone of striated muscle fiber represents both thick and thin filaments" is incorrect. The H-zone only represents thick filaments.

**Final Answer**: The statement is false; the H-zone represents only thick filaments.

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