When a muscle contracts, the

Q. When a muscle contracts, the

1. Transverse tubules shorten, the myofibrils and sarcoplasmic reticulum close together
2. Thin filaments and thick filaments of the sarcomere shorten
3. Light chains dissociate from the heavy chains of myosin
4. H bands and I bands of the sarcomere shorten because the thin filaments and thick filaments side past each other

Answer: H bands and I bands of the sarcomere shorten because the thin filaments and thick filaments side past each other