Correct Answer: A

Rationale: The correct answer is A: 'Blood clotting, transmission of nerve impulses, muscle contraction and relaxation.' Calcium plays a crucial role in various physiological functions such as blood clotting, transmission of nerve impulses, muscle contraction and relaxation, membrane permeability, and activation of certain enzymes. Choice B is incorrect because while calcium is involved in calcium homeostasis, it is not the only role it plays in the body. Choice C is incorrect as calcium indeed has several known metabolic functions, and it is not solely for preventing caries. Choice D is also incorrect as the functions mentioned are primarily carried out by other nutrients and not specifically by calcium.

Correct Answer: D

Rationale: Macronutrients are nutrients required by the body in large amounts to provide energy and include carbohydrates, fats, and proteins. While protein is essential for the body, it is not classified as a macronutrient. Proteins are made up of amino acids and serve various functions in the body, such as building and repairing tissues, but they are not a direct energy source like carbohydrates and fats. Therefore, protein is the exception among the listed options, making it the correct answer. Choice A, Fat, Choice B, Polyunsaturated fatty acids, and Choice C, Carbohydrate, are all examples of macronutrients that provide energy and support various bodily functions.

Correct Answer: C

Rationale: Multiple exposures of small quantities are considered most cariogenic. The total amount of dietary fermentable carbohydrate seems to matter less than the form and frequency in which it is consumed. Having multiple exposures of even small quantities of fermentable carbohydrate throughout the day promotes a highly cariogenic environment in the mouth. Choices A and B, involving single exposures, are less cariogenic as they do not sustain the fermentation process over time. Choice D suggests a beneficial practice by chewing sugarless gum after exposures, which can reduce the risk, making it less cariogenic compared to multiple exposures of small quantities.

Correct Answer: B

Rationale: A deficiency in iron can lead to various symptoms, such as microcytic anemia, fatigue, faulty digestion, blue sclerae, pale conjunctivae, and tachycardia. Iron-deficiency anemia may be caused by inadequate dietary intake; accelerated demand or losses; and inadequate absorption secondary to diarrhea, decreased acid secretions, or antacid therapy. Iron deficiency is frequently the result of postnatal feeding practices and has a serious impact on growth and mental and psychomotor development in infants and children. Choices A, C, and D are incorrect as zinc deficiency typically presents with symptoms like impaired wound healing, taste abnormalities, and hair loss; sodium deficiency can lead to symptoms such as muscle cramps, dizziness, and confusion; and potassium deficiency may cause muscle weakness, fatigue, and abnormal heart rhythms.

Correct Answer: B

Rationale: Both statements are false. While Healthy People (HP 2020) has contributed to a reduction in deaths from cardiovascular disease, stroke, and some cancers, it did not result in decreased dental caries in children aged 2 to 4 years and adults aged 53 to 44 years. Therefore, the correct answer is B. Choice A is incorrect because the second statement is false. Choice C is incorrect as the first statement is also false. Choice D is incorrect as the second statement is false.