77. Which of the following descriptions about muscle and skeletal system is NOT true?
(A) The strength of a muscular contraction is determined by the number of neurons delivering action potentials.
(B) Skeletal, cardiac, and smooth muscle all have transverse tubules.
(C) A hydrostatic skeleton consists of fluid held under pressure in a closed body compartment.
(D) Gap junctions provide direct electrical coupling between the cardiac muscle cells.
(E) Calcium ions cause smooth muscle contraction by binding to calmodulin.