Correct Answer: B

Rationale: Burns on the lips and singed nasal hairs are indicative of an inhalation injury. This suggests that the child has likely inhaled hot gases or smoke, leading to damage in the respiratory tract. Choice A, chemical burn, is incorrect because the symptoms described are more aligned with inhalation rather than direct contact with chemicals. Choice C, electrical burn, is incorrect as there are no mentions of contact with an electrical source. Choice D, hot-water scald, is also incorrect as the presentation of burns on the lips and singed nasal hairs is not characteristic of scald injuries.

Correct Answer: A

Rationale: The priority nursing intervention for a child with acute lymphoblastic leukemia (ALL) receiving chemotherapy is to prevent infection. Chemotherapy compromises the child's immune system, increasing susceptibility to infections. Preventing infection is crucial to avoid potential complications such as sepsis, which can be life-threatening. Administering chemotherapy is essential for treating ALL but preventing infection takes precedence due to the increased risk of infections associated with chemotherapy-induced immunosuppression. Providing nutritional support is important for overall health but preventing infections is more critical in this context. Monitoring fluid intake is significant, but the priority is to prevent infections that can have severe consequences in an immunocompromised child.

Correct Answer: C

Rationale: The correct answer is to 'Record the best of three attempts.' This method provides an accurate measure of peak expiratory flow using a peak flow meter. By taking the best of three attempts, the child and parents can obtain a more reliable assessment of the child's lung function. Choices A, B, and D are incorrect because using the device before taking medication, during asthma attacks, or after eating does not ensure an accurate measurement of peak flow, which is essential for managing asthma effectively. Monitoring peak flow regularly and accurately can help in adjusting asthma treatment plans and assessing response to medications.

Correct Answer: D

Rationale: Asking the parents if they smoke in the home is the most relevant question as exposure to secondhand smoke can exacerbate respiratory symptoms like wheezing and difficulty breathing in children. Smoking indoors can worsen the child's condition and is crucial information for the healthcare provider to assess and address. Inquiring about child safety in the home, asking about the child's temperament, and questioning the child's diet are important aspects of care but are not directly linked to the immediate respiratory symptoms the child is experiencing.

Correct Answer: B

Rationale: The correct answer is B. Myelination occurs in a cephalocaudal (head-to-toe) pattern, improving nerve function progressively. Choice A is incorrect because myelination continues beyond 4 years of age and into adolescence. Choice C is incorrect as myelination speeds up nerve impulses rather than slowing them down. Choice D is incorrect because myelination increases the specificity and efficiency of nerve impulses, making them more focused and precise.