Dark bands of muscle fibres are made of the protein ------------while light bands are composed of …………...

Explanation

To answer the question regarding the composition of dark and light bands in muscle fibers, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Muscle Fiber Structure**: Muscle fibers exhibit an alternating pattern of light and dark bands. This pattern is crucial for muscle contraction.

2. **Identifying the Dark Bands**: The dark bands in muscle fibers are known as the A bands. These bands contain thick filaments.

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