Option C. It builds up a higher level of oxygen in the blood.
At rest, the heart pumps out about 5,000mL/min of blood. This is called the cardiac output. One can say that, at rest, the total systemic blood flow throughout the body is about 5L/min. At the extreme level of activity the heart pumps much harder and faster and is usually able to quintuple its output to about 25L/min of blood flow. This amount applies to the right side of the heart, which pumps blood to the lungs so it can pick up oxygen and drop off Carbon dioxide, and the left side of the heart that pumps it to the rest of the organs and tissues of the body.
The answer would be World Cup
Mass is constant and does not depend on gravity, Where As <span>Weight is the force something exerts from its acceleration due to gravity.
Example: </span>A 100 g sample is 100 g on the earth, on the moon, wherever. <span>Since the force of gravity varies, this amount can vary greatly depending on where the thing was weighed. Even on earth the difference in the force of gravity between different elevations is sufficient for an object's weight to be different.</span>
I would say a because he ran too much but that would be just me I think he hurt his knee from running too much more exercise but probably just aggravate his condition I could be wrong but this is what I think