Because they are aside from the nervous system, the most important systems in your body. Without these systems you would not be able to circulate nutrients, expel and transport wastes like CO2, And just about keep you alive. In healthcare, you come to know that without a heart beat or an airway, your patient will die.
Answer:
<em>A</em><em> </em><em>and</em><em> </em><em>C</em><em> </em><em>one</em><em> </em><em>of</em><em> </em><em>each</em><em>.</em><em>.</em><em>.</em><em>.</em><em>.</em><em>.</em>
