Which is an effect of short-term exposure to stress?

a. improved performance
b. lower overall health
c. improved resistance to future stressors

explain why

Agroup of 50 adult male humans were in a clinical study to determine how much niacin is toxic. during the first two weeks of the study, members of the group consumed only a formula diet that was nutritionally complete, except it contained 24 mg niacin, which is 1.5 times the rda for niacin (males). at that point in the study, all members reported feeling fine. during the next week, they were given a formula that contained 48 mg niacin. within a few days of consuming this formula, 90% of the participants reported feeling ill, and they complained of having upset stomachs and reddened facial skin. at that point, researchers gave the subjects a formula that contain 16 mg niacin. after a week of consuming the new formula, all participants reported feeling well again. based on this information, the researchers concluded that the amdr for niacin is between 16 and 24 mg/day. ul for niacin was between 24 and 48 mg/day. human requirement for niacin is 16 mg/day. eer for niacin was 16 mg/day.

The primary function of the respiratory system is to supply the blood with oxygen in order for the blood to deliver oxygen to all parts of the body. the respiratory system does this through breathing. when we breathe, we inhale oxygen and exhale carbon dioxide. this exchange of gases is the respiratory system's means of getting oxygen to the blood. respiration is achieved through the mouth, nose, trachea, lungs, and diaphragm. oxygen enters the respiratory system through the mouth and the nose. the oxygen then passes through the larynx (where speech sounds are produced) and the trachea which is a tube that enters the chest cavity. in the chest cavity, the trachea splits into two smaller tubes called the bronchi. each bronchus then divides again forming the bronchial tubes. the bronchial tubes lead directly into the lungs where they divide into many smaller tubes which connect to tiny sacs called alveoli. the average adult's lungs contain about 600 million of these spongy, air-filled sacs that are surrounded by capillaries. the inhaled oxygen passes into the alveoli and then diffuses through the capillaries into the arterial blood. meanwhile, the waste-rich blood from the veins releases its carbon dioxide into the alveoli. the carbon dioxide follows the same path out of the lungs when you exhale. the diaphragm's job is to pump the carbon dioxide out of the lungs and pull the oxygen into the lungs. the diaphragm is a sheet of muscles that lies across the bottom of the chest cavity. as the diaphragm contracts and relaxes, breathing takes place. when the diaphragm contracts, oxygen is pulled into the lungs. when the diaphragm relaxes, carbon dioxide is pumped out of the lungs. write one paragraph (at least 6 sentences) describing the path of oxygen through the respiratory system. also include why this "order of operations" is the way it is!

What is the only part of your body called that should touch the ball when setting in volleyball?