ASAP!!!!! 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.
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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.
Part 2: Because Darius has heart disease, his blood flows differently from normal, especially in response to his environment and diet. If he travels to Colorado, describe how Darius's blood flow might be different than normal in a high-altitude environment that has lower temperatures.