Correct Answer: D

Rationale: The correct answer is D because sitting steadily typically occurs closer to 6-8 months of age, not 3 or 4 months. Choice A is incorrect because sitting ability and the age of first tooth eruption are not related. Choice B and C are incorrect as most infants do not sit steadily at 3 or 4 months, and it is more common for infants to achieve this milestone around 6-8 months.

Correct Answer: D

Rationale: The correct answer is D: Rules. When discussing play in school-aged children, rules are essential as they help in structuring games and social interactions. Rules provide a framework for play, ensuring fairness and cooperation among children. Choice A, recreation, is too broad and doesn't specifically address the importance of rules in play. Choice B, ritualism, is unrelated to the concept of play in school-aged children. Choice C, physical activity, is important for overall health but doesn't capture the specific aspect of rules that are crucial in the play of school-aged children.

Correct Answer: A

Rationale: Water excess typically leads to hemodilution, resulting in a decreased hematocrit. High serum osmolality and specific gravity would indicate dehydration, while elevated BUN could suggest renal impairment or dehydration, not fluid overload.

Correct Answer: B

Rationale: Starting the IV as planned while allowing the child to express feelings afterward helps build trust and ensures the timely administration of necessary antibiotics. Delaying the procedure or changing the route could compromise the child's treatment.

Correct Answer: D

Rationale: Facial expression has consistently been validated as an indicator of pain in infants. Behavioral pain measures are most reliable for sharp procedural pain in infants. Increased heart rate and respirations are indicative of a generalized and complex response to stress, not specific for pain in infants. Thrashing of arms and legs is a reliable indicator in young children, not specifically in infants.