Nursing Elites

1. Which property of a substance measures the amount of matter per unit volume?

• A. Density
• B. Mass
• C. Weight
• D. Volume

Correct answer: A

Rationale: Density is the property of a substance that measures the amount of matter per unit volume. It is calculated by dividing the mass of the substance by its volume. Mass refers to the amount of matter in an object, weight is the force of gravity acting on an object, and volume is the amount of space an object occupies. Density specifically quantifies how tightly packed the matter in a substance is, providing a measure of compactness or concentration of matter. Therefore, the correct answer is A, Density.

2. Which of the following structures in the body is responsible for protecting the lungs and heart?

• A. Rib cage
• B. Pelvis
• C. Femur
• D. Vertebral column

Correct answer: A

Rationale: The rib cage is the correct answer. It plays a crucial role in protecting vital organs like the lungs and heart. The rib cage forms a protective barrier around these organs, shielding them from external trauma or injuries. It acts as a sturdy cage, offering structural support and safeguarding the delicate tissues and structures of the lungs and heart. The pelvis, femur, and vertebral column do not directly protect the lungs and heart; instead, they have other important functions in the body, such as supporting the body's weight, enabling movement, and protecting the spinal cord.

3. Through which structure do the kidneys reabsorb water, salts, and nutrients and return them to the body?

• A. Renal artery
• B. Renal vein
• C. Nephron
• D. Glomerulus

Correct answer: C

Rationale: The question has been corrected to specify the structure responsible for reabsorbing water, salts, and nutrients in the kidneys. The correct answer is the nephron, which is the functional unit of the kidney that performs filtration and reabsorption processes. The renal artery brings blood into the kidney for filtration, the renal vein carries filtered blood away from the kidney, and the glomerulus is a part of the nephron where filtration occurs. Therefore, the nephron is the structure that reabsorbs substances and returns them to the body.

4. In an SN2 reaction, what affects the rate of the reaction?

• A. Only the concentration of the nucleophile
• B. Only the concentration of the electrophile
• C. Neither the concentration of the nucleophile nor the electrophile
• D. Both the concentration of the nucleophile and the electrophile

Correct answer: D

Rationale: In an SN2 reaction, the rate of the reaction is affected by both the concentration of the nucleophile and the electrophile. The rate-determining step involves the nucleophile attacking the electrophile, so the concentrations of both species will impact the reaction rate. Increasing the concentration of the nucleophile increases the frequency of nucleophilic attacks, while increasing the concentration of the electrophile provides more opportunities for the nucleophile to react. Therefore, the correct answer is that both the concentration of the nucleophile and the electrophile affect the rate of the SN2 reaction. Choices A, B, and C are incorrect as they do not consider the interplay between the nucleophile and the electrophile in determining the overall reaction rate in an SN2 mechanism.

5. Which term refers to the condition where a muscle shortens in length while generating force, leading to movement at a joint?

• A. Isometric contraction
• B. Eccentric contraction
• C. Isotonic contraction
• D. Concentric contraction

Correct answer: D

Rationale: Concentric contraction refers to the condition where a muscle shortens in length while generating force, leading to movement at a joint. This type of contraction is commonly associated with the lifting phase of an exercise where the muscle is actively shortening against resistance. Isometric contraction (Choice A) involves muscle contraction without a change in muscle length, Eccentric contraction (Choice B) involves the muscle lengthening while generating force, and Isotonic contraction (Choice C) refers to muscle contraction against a constant load with a change in muscle length.

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