The two upper parts of the heart are the atriums and the bottom are the ventricles.
<span>The correct answer is D. all of the above. During the so-called "mid-life crisis," people tend to start reflecting on their mortality given that almost half of their life has already passed, evaluate their purpose in life and whether they did everything they were supposed to do, and when they realize that is not the case, they start pursuing new challenges, This is because they are afraid of dying and want to start living their lives to the fullest before it's too late.</span>
1. cardiovascular exercise
2. steady state
3. oxygen deficit
