Studies suggest that leukoplakia is resolved by excess vitamin A (a fat-soluble vitamin), retinoids, and beta-carotene. Leukoplakia is a white plaque that forms on oral mucous membranes.
- A. Both statements are true.
- B. Both statements are false.
- C. The first statement is true; the second is false.
- D. The first statement is false; the second is true.
Correct Answer: B
Rationale: Both statements are false. Studies suggest that leukoplakia, a white plaque that forms on oral mucous membranes, can be resolved by vitamin A, retinoids, and beta-carotene. Despite the potential to resolve leukoplakia, relapse is common. Also pertinent, evidence does not indicate that any of these nutrients prevent malignant transformation. The extract provided clarifies that leukoplakia is a white plaque, not an erythematous lesion, and that vitamin A, retinoids, and beta-carotene can help resolve it.
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Increasing the variety of foods often prevents nutrient excesses and toxicities. A dietary change to eliminate or increase intake of one specific food or nutrient usually alters the intake of other nutrients.
- A. Both statements are true.
- B. Both statements are false.
- C. The first statement is true; the second is false.
- D. The first statement is false; the second is true.
Correct Answer: D
Rationale: The first statement is false because increasing the variety of foods actually helps prevent nutrient excesses and toxicities. The second statement is true because making a dietary change to eliminate or increase the intake of a specific food or nutrient often leads to alterations in the intake of other nutrients. Choice A is incorrect because the first statement is false. Choice B is incorrect because the second statement is true. Choice C is incorrect because the first statement is false, even though the second statement is true.
Each of the following accurately describes features of MyPlate except one. Which one is the exception?
- A. MyPlate replaces the well-known food guide, MyPyramid.
- B. The interactive website is intended to help consumers apply personalized dietary guidance.
- C. Whereas MyPyramid was more specific in many areas, MyPlate provides more general information.
- D. Foods providing similar types of nutrients are grouped together and emphasize proportionality of food selections.
Correct Answer: C
Rationale: The correct answer is C because MyPlate actually provides more specific guidance compared to MyPyramid. MyPlate was designed to simplify the dietary recommendations for consumers by focusing on a visual representation of a plate divided into food groups, making it easier to understand and apply. Choices A, B, and D accurately describe features of MyPlate: replacing MyPyramid, providing personalized dietary guidance through an interactive website, and grouping foods with similar nutrients while emphasizing proportionality of food selections.
How is the equalization of solute concentration of intracellular fluids (ICFs) and extracellular fluids (ECFs accomplished?
- A. Semipermeable membranes.
- B. Hydration.
- C. Osmotic pressure.
- D. Perspiration.
Correct Answer: C
Rationale: The correct answer is C, osmotic pressure. Osmotic pressure within the body equalizes the solute concentration of ICFs and ECFs by shifting small amounts of water in the direction of higher concentration solute. Semipermeable membranes separate one fluid compartment from another and do not directly equalize solute concentrations. Hydration and perspiration are important elements of fluid balance but do not directly achieve the equalization of solute concentrations between ICFs and ECFs, which is primarily regulated by osmotic pressure.
Each of the following nutrients provides energy except one. Which one is the exception?
- A. Proteins
- B. Carbohydrates
- C. Fats
- D. Vitamins
Correct Answer: D
Rationale: The correct answer is D, Vitamins. While proteins, carbohydrates, and fats provide energy, vitamins do not. Vitamins are essential micronutrients that help regulate various biochemical processes in the body, such as metabolism and immunity. Choice A, B, and C are incorrect because proteins, carbohydrates, and fats are macronutrients that the body uses as a source of energy.
Each statement regarding the correlation between vitamin D and sun exposure is accurate, except one. Which is the exception?
- A. The body can produce sufficient amounts of vitamin D from sunlight.
- B. UV radiation can convert a precursor of vitamin D to vitamin D3 by penetrating uncovered skin.
- C. Sunscreen blocks the formation of vitamin D3.
- D. By the age of 70 years, the skin generally produces vitamin D at only half the level it did at the age of 20 years.
Correct Answer: C
Rationale: While UV radiation can penetrate uncovered skin and convert a precursor of vitamin D to vitamin D3, sunscreen does block the formation of vitamin D3. Sunscreen is recommended by dermatologists to prevent sunburn and reduce the risk of skin cancer. The other choices are correct: the body can produce sufficient vitamin D from sunlight, UV radiation can convert a precursor of vitamin D to vitamin D3, and skin generally produces less vitamin D as a person ages.