<prompt> Which one of the following is absent in smooth muscles?ActinMyosinTroponinMyosin adenine triphosphatase  <response>: C Troponin Smooth muscle have no troponin or tropomyosin, but they have actin and myosin. They have no sarcoplasmic reticulum, No T-tubule. No Z lines. The contraction is stimulated by extracellular ca. Latching - is the characteristic of smooth muscle. Even after the dephosphorylation of myosin, the cross bridges continue to attach in the same position for some time. There is no fixed tension relationship. 