Each statement regarding the correlation between vitamin D and sun exposure is accurate, except one. Which is the exception?

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.

Correct Answer: D

Rationale: The correct answer is D, Triglycerides. Triglycerides are a type of fat, not a carbohydrate. Monosaccharides, disaccharides, and polysaccharides are all classifications of carbohydrates based on the number of sugar units they contain. Monosaccharides are the simplest form with one sugar unit, disaccharides contain two sugar units, and polysaccharides have multiple sugar units linked together.

Correct Answer: D

Rationale: The oral cavity is indeed the site of various systemic disease manifestations due to multiple factors. Firstly, the rapid cellular turnover in the oral mucosa makes it susceptible to diseases. Secondly, the constant presence of microorganisms in the oral cavity contributes to the development of systemic diseases. Finally, the oral cavity being a trauma-intense environment further increases the risk of systemic manifestations. Therefore, all the provided options - rapid cellular turnover, constant attack by microorganisms, and a trauma-intense environment - play a role in making the oral cavity a site for various systemic diseases. Hence, the correct answer is 'All of the above.' Choices A, B, and C are incorrect individually as they each represent only one aspect of why the oral cavity is prone to systemic disease manifestations, whereas the correct answer encompasses all these factors.

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.

Correct Answer: A

Rationale: Both the statement and the reason are correct and related. The Institute of Medicine (IOM) recommends 18 mg of iron per day for women 19 to 50 years old, 8 mg/day for women 51 years old and older, and men 19 years old and older. During menstruation, women lose blood containing iron, leading to a higher iron requirement in premenopausal women compared to men or postmenopausal women. This increased demand aims to replenish the iron lost during this physiological process. Therefore, the statement and reason are directly linked, explaining why the RDA for iron is higher in premenopausal women than in men or postmenopausal women. Choices B, C, and D are incorrect as they do not accurately assess the relationship between the statement and the reason provided in the question.

Correct Answer: A

Rationale: Both statements are true. When rickets occurs, the alveolar bone is affected similar to other bones in the body, with the trabeculae of the alveolar bone also weakening. In addition to damaged alveolar bone caused by vitamin D deficiency, dental changes include delayed dentition and small molars. The other choices are incorrect because both statements provided are accurate based on the effects of rickets on the alveolar bone.

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.

Correct Answer: C

Rationale: Vitamin A can be stored in the liver to meet basic needs for at least 1 year. This storage capacity allows the body to have a reserve of Vitamin A to sustain its needs over an extended period. Choices A, B, and D are incorrect because they underestimate the storage capacity of Vitamin A in the liver, which can last longer than these durations.

Correct Answer: A

Rationale: Both the statement and the reason are correct and related. Inadequate intake of vitamin A in lower socioeconomic groups is due to a lack of resources to purchase and consume vegetables and fruits. This is supported by the fact that the average intake in the United States meets the Recommended Dietary Allowance (RDA) for vitamin A intake, except in lower socioeconomic groups. These individuals often lack the financial means to buy, prepare, and eat a variety of fruits and vegetables, leading to deficiencies. It's important to note that because vitamin A can be stored in the liver, most adults have sufficient quantities to maintain health. Choices B, C, and D are incorrect because the statement and reason are both accurate and logically connected, as the lack of resources directly impacts the ability to obtain necessary sources of vitamin A.