A Muscle Fiber Contracts by a Sequence of Events Initiated

Multiple Choice

A muscle fiber contracts by a sequence of events initiated by the binding of acetylcholine to its receptor.Which of the following is the correct sequence? I-The calcium-troponin complex pulls tropomyosin away from the myosin binding sites of actin.II-The freed-sites of actin bind to myosin to form cross bridges.III-Calcium ion binds to the troponin.

A) II, III, and I
B) III, II, and I
C) III, I, and II
D) I, III, and II