Correct Answer: C

Rationale: The statement is correct, but the reason is not correct. A major difference between fat-soluble and water-soluble vitamins is that the body is able to store larger amounts of fat-soluble vitamins. Vitamins A and D are stored for long periods; therefore, minor shortages might not be identified until drastic depletion has occurred. Observable signs and symptoms of a dietary deficiency are often not identified until they are in an advanced state. Water-soluble vitamins, on the other hand, are not stored in the body and are excreted in the urine if taken in excess, making it harder to reach toxic levels.

Correct Answer: B

Rationale: The correct answer is B. Magnesium plays an important role in maintaining calcium homeostasis and preventing skeletal abnormalities. It is involved in more than 300 enzymatic reactions, including energy metabolism, insulin activity, and glucose use. Magnesium is vital to the structural integrity of heart muscle and other muscles and nerves. While magnesium does play a role in blood clotting, nerve impulses, muscle contraction, relaxation, ATP energy release, and metabolism of fats, carbohydrates, proteins, the primary physiologic role of magnesium in the body is related to calcium homeostasis and maintaining the structural integrity of the heart muscle. Choice A is incorrect because it includes functions of magnesium, but they are not its primary physiologic role. Choice C is incorrect as magnesium has several known metabolic functions. Choice D is incorrect because although magnesium is involved in ATP energy release and metabolism, its primary role is related to calcium homeostasis and structural integrity of muscle.

Correct Answer: C

Rationale: The first statement is true; the second is false. Complex carbohydrates are also called polysaccharides and contain more than 10 monosaccharides. Choice A is incorrect because the second statement is false. Choice B is incorrect because the first statement is true. Choice D is incorrect because the second statement is false.

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: 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.