What happens to the length of the A, H and I bands as the sarcomere contracts?

Explanation

To understand what happens to the lengths of the A, H, and I bands during sarcomere contraction, we can break it down into the following steps:

### Step-by-Step Solution:

1. **Identify the Sarcomere Structure**:
- The sarcomere is the basic unit of muscle contraction and consists of thick (myosin) and thin (actin) filaments.
- The A band is the region that contains the thick filaments (myosin), while the I band is the region that contains the thin filaments (actin). The H zone is the area within the A band where there are only thick filaments and no thin filaments.

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