Biology · Gaseous Exchange

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 30-40 times a minute (100 litres of air) during exercise.

15-20 times per minute – This range is typically seen during light activity or mild exercise but is still close to a resting breathing rate. During intense exercise, the breathing rate goes beyond this range, making this option incorrect for moderate or vigorous workouts.

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 30-40 times a minute (100 litres of air) during exercise.

20 times per minute – This is close to a normal resting breathing rate for an adult, which is around 12-20 breaths per minute. However, during exercise, the body requires more oxygen, and the breathing rate increases significantly beyond 20 breaths per minute. So, this option is incorrect.

10-20 times per minute – This is a more accurate estimate of the breathing rate during moderate to intense exercise. When the body is active, oxygen demand increases, and the lungs work harder to supply more oxygen, often raising the breathing rate to around 30-40 breaths per minute. So, this is the most suitable choice among the given options.