According to sliding filament theory, which band/ zone does not change in width?

Explanation

### Step-by-Step Solution:

1. **Understanding the Sliding Filament Theory**:
- The sliding filament theory explains how muscle contraction occurs at the molecular level. It describes the interaction between two types of filaments in muscle fibers: actin (thin filament) and myosin (thick filament).

2. **Components of Sarcomeres**:
- Muscle fibers are made up of units called sarcomeres. Each sarcomere contains different zones and bands, including the A band, I band, and H zone.

...