Nursing Elites

1. What element is responsible for the green color of leaves?

• A. Magnesium
• B. Iron
• C. Copper
• D. Zinc

Correct answer: A

Rationale: Magnesium is the correct answer. It is essential for the formation of chlorophyll, the green pigment in plants that is crucial for photosynthesis. Chlorophyll absorbs sunlight and uses its energy to convert carbon dioxide and water into glucose and oxygen. Iron, copper, and zinc do not play a direct role in the green color of leaves. Iron is more related to processes like electron transport, copper is involved in enzyme functions, and zinc contributes to the synthesis of plant growth regulators.

2. What happens when the diaphragm contracts?

• A. Air is expelled from the lungs.
• B. The lungs expand to allow air intake.
• C. The vocal cords vibrate to produce sound.
• D. The trachea narrows to control airflow.

Correct answer: B

Rationale: When the diaphragm contracts, it moves downward, creating more space in the chest cavity. This expansion of the chest cavity causes the lungs to expand as well, allowing air to be drawn into the lungs during inhalation. Therefore, the correct answer is that the lungs expand to allow air intake when the diaphragm contracts. Choices A, C, and D are incorrect because when the diaphragm contracts, it does not expel air from the lungs, cause the vocal cords to vibrate, or narrow the trachea to control airflow.

3. Why is the lining of the stomach covered with rugae?

• A. Rugae increase the output of gastric juices.
• B. Rugae increase the surface area of the stomach.
• C. Rugae increase the permeability of the stomach walls.
• D. Rugae increase the types of nutrients that can diffuse.

Correct answer: B

Rationale: Rugae are folds in the stomach lining that increase its surface area. This increased surface area allows for more efficient digestion and absorption of nutrients in the stomach. Choice A is incorrect because rugae do not directly affect the output of gastric juices. Choice C is incorrect because rugae do not impact the permeability of the stomach walls. Choice D is incorrect because rugae do not influence the types of nutrients that can diffuse.

4. What is the function of valves in arteries?

• A. To maintain high blood pressure for the proper diffusion of nutrients in capillaries.
• B. To prevent backflow of blood due to high pressure away from the heart.
• C. As a vestigial trait from evolution, like the appendix, that serves no purpose.
• D. Valves are absent in arteries but present in veins.

Correct answer: B

Rationale: Valves in arteries serve the crucial function of preventing backflow of blood. Arteries carry blood at high pressure away from the heart, and the valves ensure that blood flows in one direction, towards the capillaries, to maintain efficient circulation. Without these valves, there would be a risk of blood flowing backward, compromising the effectiveness of blood circulation in the body. Choices A, C, and D are incorrect. Choice A incorrectly suggests that valves maintain high blood pressure for nutrient diffusion in capillaries, which is not their function. Choice C inaccurately compares valves to vestigial traits, like the appendix, implying they serve no purpose, which is untrue. Choice D is incorrect as valves are indeed present in arteries to regulate blood flow, not just in veins.

5. What property of a substance measures the amount of matter per unit volume?

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

Correct answer: C

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 an object 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. Therefore, in this context, density is the correct answer as it specifically relates to the concentration of matter within a given volume.

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