Which factor best explains why the true prevalence of sexually transmitted infections (STIs) is often underestimated in national surveillance data?

Which statement best differentiates ovarian cancer from other gynecologic malignancies?

A 2-year-old boy is brought to clinic for a routine well-child visit. He is asymptomatic, but laboratory screening reveals a hemoglobin of 9.5 g/dL, mean corpuscular volume (MCV) of 68 fL (reference: 70–86 fL), and low serum ferritin. His diet consists mainly of cow’s milk and few fruits or vegetables. Physical examination is unremarkable. Which of the following is the most likely diagnosis?

Which mechanism best explains the reactivation of the hypothalamic-pituitary-gonadal (HPG) axis at puberty?

Which clinical presentation most accurately distinguishes genital herpes from trichomoniasis or pediculosis pubis?

Which combination of hormonal alterations best reflects the metabolic and inflammatory state of obesity?

A 67-year-old man presents with progressive fatigue, bone pain in his lower back, and unintentional weight loss. Laboratory results show:TestResultReference RangeCalcium11.8 mg/dL8.5–10.5 mg/dLCreatinine2.0 mg/dL0.6–1.2 mg/dLHemoglobin9.2 g/dL13.5–17.5 g/dLTotal protein9.5 g/dL6.0–8.3 g/dLPeripheral smear shows rouleaux formation, and serum protein electrophoresis reveals an M-protein spike.Which finding best confirms the underlying diagnosis and guides initial management?

In SIADH, which physiologic mechanism directly leads to hyponatremia and hypoosmolality?

A patient’s CBC shows: Hgb 10 g/dL, Hct 35%, MCV 77 fL, MCHC 30 g/dL, RDW 20%. Which pattern most strongly supports iron-deficiency anemia?

The increasing concentration of workers into industrial cities led to their living standards declining, but had few consequences for disease in this era of progress.