The Journal of the American Heart Association has reported that travel to high altitudes could be dangerous for people with heart conditions. Darius is planning a visit to Colorado, which has some of the highest elevations in the United States and can reach temperatures as low as 3 degrees Celsius (37.4 degrees Fahrenheit). He is an elderly man with a history of heart disease. Outline of the human body with an illustration of the heart, arteries, and veins of the circulatory system. A vein in the upper arm is labeled A, and an artery in the hand is labeled B. Public Domain Part 1: Blood circulates throughout the body, carrying oxygen and nutrients, traveling in a loop, and arriving back at its starting point. In the diagram above, point A represents a vein in the upper arm. Point B represents a capillary in the hand. Describe the pathway that a red blood cell would take to get from point A to point B. Include the function of the red blood cell in your answer.