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: D

Rationale: The correct answer is D, Osmosis. Osmosis is the process where water moves from an area of low solute concentration to an area of high solute concentration. This movement equalizes the solute concentration in intracellular and extracellular fluids. Choices A, B, and C are incorrect because they do not describe the movement of water based on solute concentration levels.

Correct Answer: D

Rationale: Iron, fiber, and B vitamins are most likely to become insufficient when carbohydrates are eliminated from the diet to lose weight. Carbohydrates are a primary source of B vitamins and fiber in the diet. Iron can also be obtained from plant-based sources like legumes and whole grains, which are often eliminated when carbohydrates are restricted. Choices A, B, and C are incorrect because protein, vitamin K, vitamin A, and vitamin C are not primarily sourced from carbohydrates and are less likely to become insufficient solely due to carbohydrate elimination.

Correct Answer: C

Rationale: The correct answer is C. DRIs do not specifically address individuals with disease states; they are intended for the general healthy population. Choice A is correct because DRIs indeed replace the older recommended daily allowances. Choice B is correct as current DRIs aim to estimate required nutrients to enhance long-term health. Choice D is accurate as DRIs also attempt to establish maximum safe levels of tolerance for nutrients.

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.