The answer is option D "<span>The ability of the heart and lungs to deliver oxygen to the muscles during exercise".
Reason:
Cardiovascular fitness is the heart, and lungs also how oxygen supplies the heart and lungs with oxygen during a activity. Its also not option A because the body is always working never resting unless the person is dead. Its not option B because cardio is the heart and lungs not muscles. Its also not option C because the heart and lungs DOES NOT take blood from the muscles thats what veins are for to transport blood and oxygen around the body. Therefore the answer is option D.
