Question

during heavy exercise the breathing rate increased due to

(a) lack of carbon dioxide
(b) lack of oxygen
(c) abundance of oxygen
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Answer 1

Explanation:

When you exercise and your muscles work harder, your body uses more oxygen and produces more carbon dioxide. To cope with this extra demand, your breathing has to increase from about 15 times a minute (12 litres of air) when you are resting, up to about 40–60 times a minute (100 litres of air) during exercise.