Structure typically seen at the border between the renal cortex and medulla include:

Correct Answer: D

Rationale: Arcuate arteries/veins mark cortex-medulla border not vasa recta (medulla), stellate (cortex), peritubular (cortex), or interlobular (cortex). This repeats Q32, key for circulation, contrasting with other locations.

Correct Answer: C

Rationale: Polycystic kidney results from failed DCT-collecting tubule fusion not PCT-DCT, Bowman's-PCT, or calyceal issues; cysts form at this junction. This pinpoints defect, critical for pathology, contrasting with other nephron stages.

Correct Answer: C

Rationale: Urachus (allantois remnant) connects umbilicus to bladder apex not neck, base, or penis; 'abus' likely OCR error for apex. This defines urachal path, critical for anomalies, contrasting with misplacements.

Correct Answer: A

Rationale: Renin activates angiotensin cleaves angiotensinogen to angiotensin I (e.g., JGA response to low BP), triggering RAAS. Vitamin D activation is kidney's calcitriol role not renin. RBC stimulation is erythropoietin not renin. Vasoconstriction is angiotensin II downstream. Renin's angiotensin initiation distinguishes it, critical for BP regulation, unlike unrelated or subsequent effects.

Correct Answer: C

Rationale: Transitional epithelium allows bladder expansion stretches with urine (e.g., multilayered, ~500 mL). Rugae aid but aren't primary folds alone insufficient. Villi are intestinal not bladder. Pseudostratified is respiratory not here. Epithelium's stretch distinguishes it, critical for capacity, unlike folds or wrong tissues.