I don't see what the "following" is but what ever it is the answer is most likely abstinence.
IF YOUR WORKING ON PLATO THE ANSWER IS GOING TO BE ..........C
Acute exposure to high altitude can affect the cardiovascular system by decreasing oxygen in the blood (acute hypoxia). It also increases demand on the heart, adrenaline release and pulmonary artery pressures.
I hope this helped:))
Ok when we inhale we are letting oxygen inside of us, that oxygen that we inhale helps our blood move around our bodies. When we breath out taking out all the old air thats called carbon dioxide and it is very dangerous because it can make us stop breathing if we dont find new oxygen fast. Please if you need more info just private message me.