Juxsta medullary nephrons:

Correct Answer: C

Rationale: Juxtamedullary nephrons (15-20%) have large glomeruli near the cortex-medulla junction and long loops with vasa recta not 80%, surface glomeruli, or peritubular capillaries. This distinguishes their role in urine concentration, critical for medullary gradient, contrasting with cortical nephrons.

Correct Answer: C

Rationale: Ureter has transitional epithelium, two muscle layers above, three below, and a stellate lumen not a serosa (retroperitoneal). This corrects ureter anatomy, key for histology, contrasting with peritoneal structures.

Correct Answer: A

Rationale: Praziquantel disrupts schistosome membranes via Ca2+ influx not Mg2+, Na+, or K+. This specifies antiparasitic action, key for schistosomiasis treatment, contrasting with other ions.

Correct Answer: C

Rationale: Triamterene (K+-sparing) can reduce free water clearance, causing antidiuresis not loop (bumetanide), thiazide (chlorthalidone), or osmotic (urea). This distinguishes paradoxical effect, key for electrolyte therapy, contrasting with typical diuresis.

Correct Answer: D

Rationale: JG cells secrete renin and are in afferent arterioles not efferent, DCT (macula densa), or glomerulus. This specifies renin source, key for RAAS, contrasting with mislocations.