<prompt> The site where myosin heads to action in skeletal muscles are covered byTropomyosinTroponin oCalciumNone of the above  <response>: In resting muscle, troponin I is bound to actin and tropomyosin covers the site where myosin head interacts with actin. Ref: Ganong;s Review of medical physiology;25th edition; pg: 104. 