Physiology Skeletal muscles: A Contracts when calcium is taken up by sacroplasmic reticulum B Contracts when actin and myosin filaments shorten C Contraction is initiated by calcium binding to troponin D Contraction is initiated by calcium binding to tropomyosin 💡 Explanation Skeletal muscles: ✓ Correct Answer: C. Contraction is initiated by calcium binding to troponin