Kristen is running half a marothon. By her tenth minute of running her breathing rate has increased from her resting rate. How are her tissues responding to her running.

The question is incomplete as it does not have the options which are:

They need more oxygen to function, so gas exchange needs to increase.  Explanation:

In the given question, Kristen is doing physical exercise for a long time as she is running in half marathon.

As a result of continuous running her breathing rate has increased because the physical exercise requires energy in the form of ATP.

The formation of ATP in the body is the result of the cellular respiration which takes place in the mitochondria which require oxygen and oxygen in the body is inhaled only through the breathing. So, more production of the ATP requires more oxygen and therefore more breathing.

Thus, the selected option is correct.