The question: What large muscle groups does cardiovascular exercise generally utilize? Remember, this is not about what is a "target" of exercise but what actual muscles help all this exercising happen.

I responded with the heart and lungs, which he responded to;
The heart is a muscle in construction, but not in function since it does not affect the bodily movement of the limbs or torso. It is more properly termed an "organ" of the body. Likewise, the lungs themselves are most definitely NOT muscles but organs.

Anyone know what the answer is...