Each statement is true of calcium within saliva, except one. Which is the exception?

Correct Answer: D

Rationale: The correct answer is D. Calcium within saliva does not increase dental caries; in fact, the buffering action provided by calcium and phosphate in saliva inhibits caries formation by preventing the dissolution of enamel by plaque biofilm. Choice A is correct as saliva is indeed supersaturated with calcium. Choice B is correct as saliva serves as a source of calcium to mineralize an immature or demineralized enamel surface. Choice C is correct as calcium and phosphate in saliva do provide a buffering action to protect teeth from acids.

Correct Answer: B

Rationale: Tocopherol, Choice B, is not a form of vitamin K; it is another name for vitamin E. Phylloquinone (Choice A), menaquinone (Choice C), and menadione (Choice D) are all forms of vitamin K. Phylloquinone is vitamin K1 found in green plants, menaquinone is vitamin K2 produced in the large intestine and found in animal tissues, and menadione is a synthetic form of vitamin K. Therefore, Choice B is the correct answer because it does not belong to the vitamin K group, unlike the other options.

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.

Correct Answer: D

Rationale: The correct answer is D. Water regulates body temperature by evaporating as perspiration from the skin, not by pooling. When sweat evaporates from the skin, it takes away heat, which helps cool the body. Choices A, B, and C are correct because water acts as a solvent for chemical reactions, maintains the stability of body fluids, and enables the transport of nutrients and excretion of waste, respectively.

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.

Correct Answer: C

Rationale: Vitamin C plays a crucial role in protecting the integrity of cellular membranes. It is essential for collagen synthesis, which is important for wound healing and maintaining skin, blood vessels, and other tissues. Choice A is incorrect as the transcription of DNA to RNA is facilitated by vitamin A. Choice B is incorrect as calcium absorption and regulation are functions of vitamin D. Choice D is incorrect as vitamin K serves as a catalyst for the synthesis of blood-clotting factors, not vitamin C.

Correct Answer: C

Rationale: The hypothalamus, located in the middle of the brain, plays a crucial role in regulating hunger and satiety. It contains specific regions that control appetite and feeding behavior. The Medulla Oblongata (Choice A) is responsible for regulating vital functions like heartbeat and breathing, not hunger. The Pituitary Gland (Choice B) is an endocrine gland that secretes hormones but is not primarily involved in hunger regulation. The Parathyroid (Choice D) is responsible for regulating calcium levels in the body and not related to hunger or satiety.

Correct Answer: A

Rationale: The correct answer is A: Elderly. The other choices provided, low income, vegans, and chronic disease, alcoholics, are also at risk for nutritional deficiencies but the question specifically asks for 4 groups out of the 12 discussed. The 12 groups at risk for nutritional deficiencies include the elderly, low income individuals, vegans, chronic disease, alcoholics, smokers, periods of growth, individuals with medical conditions, physical stress, physiological stress, those on polypharmacy, and those with inadequate intake. The question focuses on identifying 4 out of these 12 groups, making 'Elderly' the correct choice.

Correct Answer: A

Rationale: The correct answer is A, Beans. Beans are known to be a good source of protein compared to the other options provided. While red peppers, asparagus, and celery are nutritious vegetables, they do not contain as much protein as beans do. Red peppers are high in vitamin C, asparagus is rich in vitamins and minerals, and celery is low in calories and a good source of fiber, but they are not significant sources of protein.