Which of the events below is the FIRST to occur prior to a muscle cell contracting? A. ATP binds to myosin. B. ADP detaches from myosin. C. the active site on actin is exposed. D. Ca ++ is released from the sarcoplasmic reticulum.
Option D. The release of Ca from wherein it's far stored (withinside the SR) is necessary earlier than the lively binding cite of actin may be exposed.
