its half of the studying process because the other half is actually putting that material to use. it is still important because you couldn't practice the material, without said material.
Creating study materials is considered "half of the studying" because study materials are like flashcards and notes, so having things like this is already helping the process getting started. I think this is an important step in the studying process because without any of these facts and information on paper or electronically it would be more difficult to find what you should study and you need something that you can go over to help prepare you for the assignment.
Your answer would be B : resting heart rate The reason why this is your answer is because are body need the oxygen to keep your body flowing from not having a storke