Correct Answer: C

Rationale: The correct answer is C: Calcium. Calcium is essential for maintaining bone health and is crucial in preventing osteoporosis. Adequate calcium intake, along with vitamin D, is vital for bone strength. While other minerals and vitamins are also important for overall health, in the context of preventing osteoporosis, calcium plays a primary role. Potassium (Choice A), Magnesium (Choice B), and Vitamin B12 (Choice D) are important for various bodily functions but are not as directly linked to preventing osteoporosis as calcium.

Correct Answer: B

Rationale: The correct answer is 55 mg/dL. The standard range for serum glucose levels is typically 60-115 mg/dL. A serum glucose level of 55 mg/dL falls below this range, indicating hypoglycemia. Options A, C, and D are within the standard range for serum glucose levels and would not be considered abnormal for a 30-year-old male.

Correct Answer: C

Rationale: The correct answer is the Vastus lateralis when giving an intramuscular injection to an infant. The Vastus lateralis muscle, located in the thigh, is the preferred site for infants as it has a larger muscle mass and is well-developed, making it suitable for injections. The Ventrogluteal region and Dorsogluteal region are not recommended for infants due to their smaller muscle mass and potential risk of damaging nearby structures. The Deltoid muscle is typically used for older children and adults, not infants.

Correct Answer: C

Rationale: The correct answer is 22 gauge. A 22-gauge needle is recommended for school-age children, toddlers, and adolescents due to their muscle mass and tolerance. In infants, a smaller gauge (23-25) is preferred as their muscles are less developed and more sensitive. Choice A, 27 gauge, is too thin for an intramuscular injection in a 12-year-old boy. Choice B, 25 gauge, is more suitable for infants than for a 12-year-old. Choice D, 20 gauge, is too thick and not typically used for intramuscular injections in children.

Correct Answer: A

Rationale: The correct answer is the 8-year-old boy with vomiting, slower movements, and a history of an atrioventricular shunt placement. This report requires immediate attention because the symptoms could indicate a blocked shunt, which is a serious medical condition needing urgent evaluation and intervention. Slower movements in the context of an atrioventricular shunt history could suggest increased intracranial pressure. The other choices involve less urgent issues: choice B describes post-exercise pain, choice C presents with a low-grade fever and headache that could be due to a mild infection, and choice D reports itching associated with a cast, which is a common issue and less critical compared to a potentially blocked shunt.