Correct Answer: C

Rationale: An essential nutrient is a substance that cannot be made in sufficient quantities by the body itself, so it must be obtained from the diet. Choice A is incorrect because essential nutrients are required in specific amounts, not necessarily large quantities. Choice B is incorrect as essential nutrients cannot be synthesized by the body at all. Choice D is incorrect because although essential nutrients may be used in the synthesis of other compounds, that is not the defining characteristic of an essential nutrient.

Correct Answer: A

Rationale: The main purpose of Recommended Dietary Allowances (RDAs) is to provide guidelines for nutrient intakes that meet the needs of most healthy people. Choice B is incorrect because RDAs aim beyond just survival requirements. Choice C is incorrect because establishing maximum safe levels is the role of Tolerable Upper Intake Levels (ULs). Choice D is incorrect because preventing chronic diseases is more associated with Dietary Reference Intakes (DRIs) like Adequate Intakes (AIs) and Tolerable Upper Intake Levels (ULs). Therefore, the correct answer is A.

Correct Answer: B

Rationale: The correct answer is B: Ensure strict infection control measures. Children with acute lymphoblastic leukemia (ALL) who are undergoing chemotherapy have compromised immune systems, making them highly susceptible to infections. Implementing strict infection control measures, such as hand hygiene, limiting exposure to sick individuals, and maintaining a clean environment, is essential to prevent infections. Choice A is incorrect because avoiding all physical activity may not be necessary as long as the child's activity level is appropriate. Choice C is incorrect because increasing daily caloric intake is important to support the child's nutritional needs during treatment. Choice D is incorrect because limiting fluid intake is not typically recommended unless specifically advised by the healthcare provider.

Correct Answer: A

Rationale: Encouraging joint mobility and physical therapy is crucial in managing juvenile idiopathic arthritis (JIA). This approach helps maintain joint function, reduce stiffness, and improve the overall quality of life for children with JIA. Restricting all forms of exercise (Choice B) is not recommended, as appropriate physical activity is beneficial for joint health and overall well-being. Increasing sugar intake (Choice C) is not a recommended practice for managing JIA, as a healthy diet is important for overall well-being and can help reduce inflammation. Using only oral medications (Choice D) may not be sufficient for managing JIA, as a comprehensive treatment plan often includes a combination of medications, physical therapy, and other interventions to effectively manage the condition.

Correct Answer: B

Rationale: In laryngotracheobronchitis (croup), a child may become restless due to poor oxygenation. Increasing the oxygen concentration in the oxygen tent is crucial to improve oxygenation levels and manage symptoms effectively. Restraint is not appropriate in this situation, as it may cause distress and worsen the child's condition. Taking the child to the playroom is not indicated when the child requires oxygen therapy. While comforting the child is important, the priority in this scenario is to optimize oxygen delivery to improve respiratory distress.