The urinary system develops from:

Correct Answer: B

Rationale: The urinary system arises from intermediate mesoderm (nephrogenic cord) not paraxial (somites), lateral plate (body cavities), all, or none. Intermediate mesoderm forms pronephros, mesonephros, and metanephros, driving kidney and ureter development. This distinguishes germ layer roles, critical for embryogenesis, contrasting with non-urinary mesoderm sources.

Correct Answer: D

Rationale: Male urethra has endodermal (vesicourethral, sinus) and ectodermal (glans) origins not just one or mesodermal alone; 'all' fits broadly. This reflects mixed lineage, critical for urethral development, contrasting with single-layer views.

Correct Answer: A

Rationale: Amino acids aren't nitrogenous wastes reabsorbed or metabolized, not excreted (e.g., PCT). Urea, from protein breakdown major waste. Uric acid, from purines excreted. Creatinine, from muscle waste product. Amino acids' conservation distinguishes them, critical for nitrogen reuse, unlike waste products excreted.

Correct Answer: A

Rationale: The hilum is the kidney's depression entry/exit for artery, vein, ureter (e.g., medial notch). Capsule is protective not an opening. Cortex is nephron-rich internal. Pyramid is medullary not entry. Hilum's gateway role distinguishes it, critical for vascular/urinary access, unlike structural zones.

Correct Answer: A

Rationale: Glomeruli are in the cortex cortical nephrons dominate (e.g., filtration zone). Medulla has fewer juxtamedullary. Pelvis collects not filters. Pyramids are medullary subset. Cortex's glomerular density distinguishes it, critical for GFR, unlike deeper or collecting areas.