Correct Answer: A

Rationale: The correct answer is to monitor for signs of infection. When a child is undergoing chemotherapy, their immune system is compromised, making them more susceptible to infections. Monitoring for signs of infection is crucial to promptly identify and treat any potential infections. Choices B, C, and D are incorrect because although monitoring for bleeding, dehydration, and pain are important aspects of care, the priority for a child receiving chemotherapy is to prevent and detect infections due to their increased vulnerability.

Correct Answer: B

Rationale: The correct answer is B: Tissue oxygen needs. Polycythemia occurs as the body's response to chronic hypoxia by increasing RBC production to enhance oxygen delivery. In tetralogy of Fallot, a congenital heart defect, the heart's structure causes reduced oxygen levels in the blood. This chronic hypoxia stimulates the bone marrow to produce more red blood cells, leading to an elevated RBC count. Choice A is incorrect as low blood pressure is not directly related to polycythemia in this context. Choice C, diminished iron level, is not the cause of polycythemia in tetralogy of Fallot. Choice D, hypertrophic cardiac muscle, is not the primary cause of the elevated RBC count in this case.

Correct Answer: A

Rationale: Epicanthal folds are a distinctive physical feature commonly observed in individuals with Down syndrome. These are horizontal skin folds that cover the inner corners of the eyes. Webbed neck (choice B) is not typically associated with Down syndrome but can be seen in conditions like Turner syndrome. Enlarged head (choice C) is not a characteristic feature of Down syndrome; however, individuals with hydrocephalus may present with this finding. Polydactyly (choice D) is the presence of extra fingers or toes, which is not a typical feature of Down syndrome.

Correct Answer: A

Rationale: A heart rate below 100 beats/min in a newborn indicates the need for positive pressure ventilation to improve oxygenation. Providing positive pressure ventilations helps in assisting the newborn's breathing efforts to ensure adequate oxygenation. Choice B, providing blow-by oxygen, may not be sufficient to address the underlying issue of inadequate breathing. Choice C, assessing the newborn's skin condition and color, is important but not the most immediate action needed for a heart rate below 100 beats/min. Choice D, starting chest compressions, is not indicated as the infant is breathing spontaneously and has a heart rate, albeit lower than normal, which does not warrant chest compressions.

Correct Answer: B

Rationale: It is recommended that a child should visit the dentist within the next few months after turning two years old. This allows for early dental check-ups to monitor oral health, detect any issues early on, and establish a good oral hygiene routine. Choice A ('Before starting school') is not as specific and may delay the child's first dental visit. Choice C ('When the first deciduous teeth are lost') is too late for the first dental visit, as preventive care should start earlier. Choice D ('At the next dental visit of a family member') is not ideal as the child's dental needs should be addressed independently of family members' visits.