Blood volume varies with 

 The normal pacemaker of the heart is the 

 The right atrium receives blood directly from 

 The normal white blood cell count is 

 Hematocrit is 

 The percentage of red blood cells in a sample of human bloo…

 The pain of angina pectoris comes from a blockage in an art…

 Athletes abuse erythropoeitin (EPO) because it 

 The radial and ulnar veins merge to form the _______ vein. 

  2.5 Hoeveel kos die kaartjies vir kinders en volwassen…