Consider the way that muscle is stimulated to move and the way that the heart is stimulated to move. based on the positions of the electrodes, what might some challenges be to measuring ecg signals during exercise?

ECG report generated after exercise may give indication of Exercise-induced arrhythmias

Explanation:

The relationship between the rate of heart beat and the exercise is linear in nature. The rate of heart beat increases linearly with the exercise till the maximum limit of heart rate. When the heart rate increases suddenly, the tachyarrhythmia develops and just after the exercise the heart rate falls suddenly thereby indicating fall in blood pressure and hence leads to precipitation of  syncope linked with vasovagal response. Thus such sudden rise and fall of heart rate may show that the person is having some problems related to conduction pathway of heart.  

the answer will be a) proteins i believe

the correct option is option d