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The alarm stage is the initial reaction to a stressor and is characterized by emotional outbursts, increased heart rate, and release of stress hormones such as adrenaline. The employee’s immediate anger and physical reaction reflect this stage. The resistance stage involves adaptation, and exhaustion occurs after prolonged stress. “Failure” is not a recognized stage of the stress response. The NEX Science exam frequently tests physiological and psychological responses to stress, making alarm the correct answer.

Extension is the movement that increases the angle between two bones at a joint. When the arm straightens at the elbow, the angle between the radius and the humerus increases, which is extension. Flexion decreases the angle between bones, circumduction is a circular movement, and retraction refers to pulling a structure backward. Understanding anatomical movement terms is essential for the NEX Science exam, especially in questions related to joints and motion.

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When oxygen levels are insufficient during intense exercise, muscle cells switch from aerobic respiration to anaerobic respiration. In this process, pyruvic acid is converted into lactic acid. The production of lactic acid allows glycolysis to continue generating ATP in the absence of oxygen. However, lactic acid buildup contributes to muscle fatigue and soreness. Carbon dioxide is primarily produced during aerobic respiration, and hydrogen ions are a byproduct but not the main substance emphasized in anaerobic respiration. The NEX Science exam frequently tests metabolic pathways related to exercise and energy production, making lactic acid the correct answer.

This question tests understanding of osmosis and tonicity, which are frequently assessed on the NEX Science exam, especially in physiology-related contexts. Plain water ishypotoniccompared to the fluid inside red blood cells. When red blood cells are placed in a hypotonic solution, water movesintothe cells by osmosis because water flows from an area of lower solute concentration to higher solute concentration. As water enters the red blood cells, they swell. If too much water enters, the cells can burst in a process calledhemolysis. The correct image therefore shows enlarged, rounded red blood cells that may appear ruptured. Normal biconcave cells indicate an isotonic environment, while shriveled or spiky cells occur in a hypertonic solution. Sickle-shaped cells are related to a genetic disorder and are not caused by osmotic changes. The NEX exam often emphasizes patient safety concepts, including why plain water should never be infused intravenously.