Final answer:
The two body systems most likely involved in an experiment focusing on the effect of exercise on pulse rate are the respiratory and cardiovascular systems, as exercise increases the body's demand for oxygen and blood circulation.
Step-by-step explanation:
When students aim to determine the effect of exercise on pulse rate, the two body systems involved are likely the respiratory system and the cardiovascular system. Exercise increases the demand for oxygen and nutrients in the tissues, particularly in the muscles. The respiratory system works to intake more oxygen through an increased breathing rate, while the cardiovascular system ensures that this oxygen, along with essential nutrients, is delivered throughout the body by increasing the pulse rate or heart rate.
The muscular and skeletal systems are also highly involved as they are the systems responsible for physical activity, but the direct effect on pulse rate is more significantly linked to the cardiovascular system's need to pump blood faster to the muscles, and the respiratory system's need to provide more oxygen, which is carried by the blood.