Correct Answer: A

Rationale: The correct answer is A: 1 year. By the age of 1 year, a baby's birth weight typically triples. This period allows for significant growth and development in infants. Choices B, C, and D are incorrect because birth weight does not usually triple by 1 month, 2 years, or 6 months of age, respectively.

Correct Answer: C

Rationale: In response to dehydration, the body compensates by shifting fluids from the interstitial spaces to the intravascular space to maintain blood pressure and perfusion to vital organs. Hemoconcentration and vasoconstriction are other compensatory mechanisms but are less immediate.

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.

Correct Answer: C

Rationale: Ensuring the dose does not exceed 15 mg/kg is critical to avoid overdose and potential liver damage. Retaking the temperature immediately or using cold compresses is not necessary, and placing a warm blanket could exacerbate the fever.

Correct Answer: D

Rationale: Using simple diagrams helps school-age children understand what to expect in a procedure, catering to their developmental level and reducing anxiety. Informing toddlers too early can increase anxiety, and parents' presence is generally comforting, not discouraging.