<prompt> Which of the following special circulations has the widest range of blood flows as pa of its contributions to both the regulation of systemic vascular resistance and the modification of resistance to suit the organs metabolic needs?Large intestineCerebralSmall intestineSkeletal muscle  <response>: Skeletal muscle accounts for about 20 of cardiac output and systemic vascular resistance. During extreme physical exeion, more than 80 of cardiac output can be directed to contracting muscles; therefore, skeletal muscle resistance becomes the primary determinant of systemic vascular resistance during exercise. 