<prompt> Which of the following triggers muscle contractionCa2 binding tropomyosinCa2 binding troponin CCa2 binding troponin IATP breakdown  <response>: Troponin and Its Role in Muscle ContractionAttached intermittently along the sides of the tropomyosin molecules are additional protein molecules called troponin.These protein molecules are actually complexes of three loosely bound protein subunits, each of which plays a specific role in controlling muscle contraction.One of the subunits troponin I has a strong affinity for actin, another troponin T for tropomyosin, and a third troponin C for calcium ions. This complex is believed to attach the tropomyosin to the actin. The strong affinity of the troponin for calcium ions is believed to initiate the contraction process.Guyton 13e pg: 78 