The exposure to which of the following early in childhood protects against the development of atopy

Correct Answer: D

Rationale: Early exposure to dogs has been linked to a reduced risk of atopy, possibly due to microbial diversity exposure that modulates immune responses. Other exposures listed do not provide protection.

Correct Answer: A

Rationale: First-generation antihistamines cross the blood-brain barrier and commonly cause sedation.

Correct Answer: B

Rationale: The correct answer is B because birth weight typically doubles around age 5 to 6 months. Therefore, a 6-month-old infant who weighed 7 pounds at birth would be expected to weigh around 15 pounds at this age.

Correct Answer: A

Rationale: The recommended IV epinephrine dose in pediatric cardiac arrest is 10 mcg/kg (0.01 mg/kg). It enhances cardiac output by increasing heart rate, contractility, and vasoconstriction, improving perfusion.

Correct Answer: A

Rationale: The mechanism of action of corticosteroids is well understood; they suppress inflammation by inhibiting cytokine production and reducing immune cell activity. They also downregulate prostaglandins and leukotrienes.