The treatment of choice for childhood onset of major depression is

Correct Answer: C

Rationale: Serotonin reuptake inhibitors (SSRIs) are preferred over older medications like tricyclics due to better safety profiles and efficacy in pediatric depression.

Correct Answer: C

Rationale: Climate change poses a major threat to food security by affecting crop yields and causing extreme weather events that disrupt agriculture.

Correct Answer: D

Rationale: Inhaled β₂-agonists are recommended for intermittent asthma symptoms as needed for relief.

Correct Answer: D

Rationale: Uncompensated respiratory alkalosis occurs when excessive breathing reduces CO2 levels, raising pH. Bicarbonate remains normal in the acute phase before renal compensation.

Correct Answer: B

Rationale: Abdominal mass is the most common presentation of pediatric Non-Hodgkin lymphoma, as it often arises from extranodal sites like the GI tract. Systemic symptoms are less frequent than in Hodgkin lymphoma.