Correct Answer: A

Rationale: The correct answer is A: 'On the back, lying flat'. Placing infants on their back to sleep is recommended to reduce the risk of sudden infant death syndrome (SIDS). This position helps ensure the baby's airway remains clear and reduces the likelihood of suffocation. Choices B, C, and D are not as safe as placing the infant on their back, as they may increase the risk of accidental suffocation or SIDS.

Correct Answer: B

Rationale: Childhood obesity is a prevalent issue in children with Down syndrome due to factors such as decreased physical activity, slower metabolism, and potential overeating tendencies. Addressing obesity is crucial to promoting healthy lifestyles and preventing associated health complications. Rickets, a condition caused by a deficiency of vitamin D, is not commonly associated with Down syndrome. While anemia can occur in individuals with Down syndrome, obesity is a more common concern. Rumination, the regurgitation of food without nausea, is not a typical nutritional problem in children with Down syndrome.

Correct Answer: C

Rationale: The correct hematocrit range for a healthy 12-month-old infant is between 37% to 47%. At this age, this range reflects the normal blood volume and red blood cell (RBC) levels in infants. Choice A (19% to 32%) is too low for a healthy hematocrit level in a 12-month-old. Choice B (29% to 41%) is also below the typical range for a 12-month-old. Choice D (42% to 69%) includes an upper limit that is higher than expected for a healthy infant, making it an incorrect option.

Correct Answer: D

Rationale: The correct answer is D: DTaP, IPV, MMR. Before starting kindergarten, the child should receive boosters of DTaP, IPV, and MMR to ensure ongoing protection against diphtheria, tetanus, pertussis, polio, measles, mumps, and rubella. Choice A is incorrect because it includes HepB instead of MMR. Choice B is incorrect as it includes HepB instead of MMR and DTaP instead of IPV. Choice C is incorrect as it includes Hib instead of IPV.

Correct Answer: D

Rationale: Preparing a toddler for a CT scan involves providing a simple explanation of the procedure to help reduce anxiety and fear. Shaving the child's head is unnecessary for a CT scan and may increase distress. Starting an IV infusion or administering sedatives may not be appropriate or necessary for all pediatric patients undergoing CT scans, especially if the child can cooperate without these interventions.