Question

Kristen is running a half marathon. By her tenth minute of running, her breathing rate has increased from her resting rate. Which statement best describes how her tissues are responding to her running?
They need more oxygen to function, so gas exchange needs to decrease.
They need more oxygen to function, so gas exchange needs to increase. 
They need more carbon dioxide to function, so gas exchange needs to increase.  They need more carbon dioxide to function, so gas exchange needs to decrease.

Answer 1

The correct answer is option They need more oxygen to function, so gas exchange needs to increase.

As the person starts a physical exercise, the workload of the muscles increase, which produces a higher demand of ATP. In order to produce ATP, the mitochondria require more oxygen and glucose to generate the ATP molecules, as a result, the demand for the oxygen is increased. Due to increase in oxygen demand, the lungs do more gaseous exchange, so that the demand of the oxygen can be fulfilled.

Answer 2

They need more oxygen so the gas exchange needs to increase