The question is incomplete, the complete question is;
A track meet is scheduled to be held in a city that is at high altitude. One of the runners lives near a beach. To improve her chances of winning a medal, the runner decides to train for a number of weeks in the mountains. She hopes that this will increase her number of red blood cells. Which function of the circulatory system does she hope to improve?
delivery of disease-fighting cells to body tissue
delivery of oxygen to body tissues
delivery of blood-clotting materials to body tissues
delivery of nutrients to body tissue
Answer:
delivery of oxygen to body tissues
Step-by-step explanation:
We all know that pressure decreases with height. At a higher altitude, the pressure of air is much lower. This causes breathing difficulty especially during a strenuous activity such as athletics.
At high altitude the breathing rate doubles. Also, additional red blood cells and capillaries are produced to carry more oxygen, delivering more oxygen to body tissues. The lungs as well increases in size.
This acclimatization to high altitude increases the level of endurance of athletes and gives them comparative advantage at sporting events.