Stress tests are performed to assess the adequacy of the amount of oxygen getting to the heart muscle and thus indicate the presence or absence of heart disease. the top number on a blood pressure reading is ; the bottom number on a blood pressure reading is

1. desertification

2. captive breeding

3. black rhinoceros

4. renewable resources

explanation:

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when you breathe in, or inhale, your diaphragm contracts (tightens) and moves downward. this increases the space in your chest cavity, into which your lungs expand. the intercostal muscles between your ribs also enlarge the chest cavity. they contract to pull your rib cage both upward and outward when you inhale.