An important difference between single-unit and multiunit smooth muscle is the
A) numerous gap junctions in single-unit smooth muscle, which allow many cells to work together as a sheet.
B) longer actin and myosin filaments in multiunit smooth muscle, which allow coordination of contraction.
C) ability of single-unit fibers to change into multiunit fibers when advantageous.
D) closely controlled individual fibers in single-unit smooth muscle to allow fine control and graded contractions by selective activation.
Answer: : A