<em>Respiration is the process by taking in oxygen and liberating carbon dioxide from the oxidation of complex organic substances.</em>
<em>Three types of respiration include internal, external, and cellular respiration. External respiration is the breathing process. It involves inhalation and exhalation of gases. Internal respiration involves gas exchange between the blood and body cells.</em><em>.</em><em>.</em><em>.</em>
