Correct Answer: D

Rationale: The Recommended Dietary Allowances (RDAs) are the best measure to describe the amounts of nutrients that should be consumed by the population. RDAs represent the average daily intake level that meets the nutrient requirements of nearly all (97-98%) healthy individuals in a particular life stage and gender group. Choice A, the Dietary Reference Intakes, provide a set of nutrient intake values but do not specifically address the average daily amount of a nutrient considered adequate for practically all individuals. Choice B, the Tolerable Upper Intake levels, focus on the maximum daily amount of a nutrient deemed safe for most healthy people, not the average daily amount needed. Choice C, the Estimated Average Requirements, reflect the average daily amount of a nutrient needed by half of the healthy individuals, which is not as comprehensive as the RDAs that cater to nearly all healthy people.

Correct Answer: D

Rationale: The correct answer is D. Carbohydrates are the body's primary source of energy, fueling daily activities and bodily functions. Choice A is incorrect because insulation and organ support are primarily provided by adipose tissue and structural proteins, not carbohydrates. Choice B is incorrect because the regulation of body temperature is mainly controlled by processes like sweating and shivering, not carbohydrates. Choice C is incorrect because structural components like proteins are responsible for building tissues and organs, not carbohydrates.

Correct Answer: A

Rationale: Frequent urination is a common sign of a urinary tract infection in older children. It is often accompanied by other symptoms such as pain or discomfort. Increased appetite (Choice B) is not typically associated with urinary tract infections. Elevated blood pressure (Choice C) is more commonly linked to conditions like hypertension, not urinary tract infections. Decreased energy levels (Choice D) can be a sign of various health issues but are not a typical symptom of a urinary tract infection.

Correct Answer: B

Rationale: Thickening the formula or breast milk with cereal is a common treatment for gastroesophageal reflux (GER) in infants. By adding cereal, the feedings become heavier, making it less likely for the stomach contents to reflux. Keeping the infant NPO (nothing by mouth) is not typically necessary for GER treatment and might not be appropriate. Placing the infant to sleep on the side is not recommended due to the risk of sudden infant death syndrome (SIDS). Switching the infant to cow's milk is also not a recommended treatment for GER as it can exacerbate symptoms due to its protein content.

Correct Answer: A

Rationale: The correct answer is A. Energy is released during the metabolism of energy nutrients. This released energy is utilized by the body for various functions. Choice B is incorrect because the metabolism of energy nutrients does not directly result in an increase in body fat. Choice C is incorrect as energy is not destroyed but rather transformed and utilized by the body. Choice D is incorrect as the metabolism of energy nutrients does not lead to a decrease in body water.