NLN NEX - Nursing Entrance Exam (Math, Science and Verbal)

The pancreas produces insulin, which regulates blood glucose levels. Without insulin, glucose cannot efficiently enter cells, leading to hyperglycemia. Removing the pancreas would therefore cause blood glucose levels to rise. This concept is directly related to diabetes physiology and is a common topic on the NEX Science exam.

This question tests understanding of predator–prey relationships, a key ecology concept on the NEX Science exam. Wolves are the natural predators of moose on Isle Royale. When the moose population was initially high, there was an abundant food supply for wolves. This allowed the wolf population to increase significantly. As the number of wolves increased, predation pressure on the moose population also increased, leading to a sharp decline in moose numbers. This inverse relationship between predator and prey populations is a classic ecological pattern. There is no evidence in the question to suggest disease, human hunting, or breeding rate differences as the primary cause. Instead, the changes in population sizes are best explained by increased predation. The NEX often assesses whether students can interpret real-world ecological data and recognize how population dynamics are influenced by natural predator–prey interactions.

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Ligaments are strong bands of connective tissue that connect bone to bone at joints. Their primary function is to stabilize joints and prevent excessive movement. When a ligament is torn, the connection between two bones is disrupted, leading to joint instability. Tendons, not ligaments, connect muscle to bone. Nerves transmit electrical signals, and arteries transport blood. The NEX Science exam frequently includes musculoskeletal system questions that require distinguishing between ligaments and tendons, making bone-to-bone the correct answer.

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The ball-and-socket joint of the upper extremity is the shoulder joint. This joint is formed by the head of the humerus (the ball) fitting into the glenoid cavity of the scapula (the socket). This structure allows for a wide range of motion, including flexion, extension, abduction, adduction, and rotation. The ribs do not participate in this joint, and the clavicle connects the scapula to the sternum but does not form the ball-and-socket articulation. Understanding joint structure and function is important for anatomy questions on the NEX Science exam. The shoulder joint’s design allows greater mobility than stability, which explains why shoulder dislocations are relatively common.

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An ionic bond forms when one atom completely transfers one or more electrons to another atom. This typically occurs between a metal and a nonmetal, resulting in the formation of positively and negatively charged ions that attract each other. In contrast, covalent bonds involve sharing of electrons. Non-polar covalent bonds share electrons equally, while polar covalent bonds share electrons unequally. Hydrogen bonds are weak attractions between molecules, not true electron-sharing or transfer bonds. The NEX Science exam frequently assesses basic chemistry principles related to bonding and molecular interactions. Because only ionic bonds involve a complete transfer of electrons, option D is correct.

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Hydrochloric acid (HCl) is a strong acid. To neutralize an acid, a base must be added. Sodium hydroxide (NaOH) is a strong base that reacts with HCl to form water and a salt (sodium chloride). This neutralization reaction reduces the acidity of the solution. The other options—HNO₃, CH₃COOH, and H₂SO₄—are all acids and would increase acidity rather than neutralize it. The NEX Science exam often tests acid–base chemistry and emphasizes recognizing common acids and bases. Since NaOH is the only base listed, option C is correct.