Answer:
Options B and D
Explanation:
In animals, gaseous exchange takes place in the alveoli in the lungs. Generally, animals breath-out (exhale) carbon dioxide and breath-in (inhale) oxygen. Thus, carbon moves from the blood in the form of carbon dioxide into the alveoli in the lungs while the oxygen inhaled moves from the alveoli in the lungs to the blood where it is transported round the body as oxyhaemoglobin.
Epidemic: <span>a widespread occurrence of an infectious disease in a community at a particular time.</span>