Correct Answer: B

Rationale: In sickle cell anemia, pain is primarily caused by the obstruction of blood flow by sickle-shaped cells. This obstruction leads to inadequate oxygen supply to tissues, resulting in tissue damage and pain. Choice A, inflammation of the vessels, is incorrect as it is not the primary cause of pain in sickle cell anemia. Choice C, overhydration, is unrelated to the pathophysiology of sickle cell anemia and would not lead to the characteristic pain experienced. Choice D, stress-related headaches, is also unrelated to the underlying mechanisms of pain in sickle cell anemia.

Correct Answer: B

Rationale: Pallor and fatigue are common signs of iron-deficiency anemia in children. Iron-deficiency anemia is characterized by a decreased production of red blood cells, leading to a paler appearance (pallor) and increased fatigue due to reduced oxygen-carrying capacity. Yellowing of the skin (choice A) is more commonly associated with liver or bile duct issues. Rapid weight gain (choice C) and increased appetite (choice D) are not typical signs of iron-deficiency anemia.

Correct Answer: C

Rationale: The correct answer is C: 'Low-phenylalanine diet.' Children with phenylketonuria (PKU) need to follow a low-phenylalanine diet to manage the condition. Phenylalanine is an amino acid found in protein-containing foods, and individuals with PKU have difficulty metabolizing it, leading to neurological damage and other complications. Therefore, restricting phenylalanine intake is crucial. Choice A, 'High-protein diet,' is incorrect because high protein intake would increase phenylalanine levels, worsening the condition. Choice B, 'Low-fat diet,' and Choice D, 'High-fiber diet,' are not the primary focus for PKU patients. The key dietary intervention for PKU is controlling phenylalanine intake, which is best achieved through a low-phenylalanine diet.

Correct Answer: A

Rationale: To assess hydration status in a child with fever and vomiting, monitoring skin turgor and mucous membranes is essential. Skin turgor refers to the skin's ability to change shape and return to normal; poor skin turgor can indicate dehydration. Mucous membranes, such as the mouth and eyes, can also provide valuable information about hydration levels. Measuring blood glucose levels (Choice B) is not directly related to assessing hydration status. Checking for signs of jaundice (Choice C) is important for liver-related issues, not hydration assessment. Assessing respiratory rate (Choice D) is crucial for evaluating respiratory function, not hydration status.

Correct Answer: B

Rationale: The primary reason most people choose the foods they eat is taste. While cost, convenience, and nutritional value also play a role in food choices, taste often takes precedence as people are more likely to select foods that they find appealing in flavor. Therefore, options A, C, and D are incorrect as taste is the chief factor influencing food choices.