6) Vessels maintain blood flow because they: [D. Depend upon body movement], especially veins of the lower extremities.
7) Kidneys regulate water volume in the blood and urine [A.], thereby affecting the volume of blood, which directly relates to pressure and flow.
8) Stronger striated muscle [D.] is a health benefit of exercise which only affects skeletal muscle, not the heart muscle (cardiac) nor blood vessels (smooth).
9) [D.] Drinking liquids immediately before a blood pressure (BP) reading would be least likely to raise BP artificially. Where as exercise, fear or anxiety, and an improper cuff size could affect the BP measurement.