Which statement is not true? A. conducting tissue of the heart is capable of clepolarizion rhythmically with?

Which statement is not true? A. conducting tissue of the heart is capable of clepolarizion rhythmically with no external stimulus from the nervous system B. intercalated discs of cardiac tissue fascillitate impulse conduction from cell to cell C. atrioventrivicular node is normal pacemaker of heart D. atria of heart contract as a single unit and 2 ventricles contract as a single unit after a short delay E. ectopic (unusual) pacemaker and the resulting ectopic beats can disrupt blood flow