Renin acts on to convert it to angiotensin I.

Correct Answer: B

Rationale: Renin cleaves angiotensinogen to angiotensin I, not angiotensin II (product), ACE (enzyme), or aldosterone (downstream). This initiates RAAS, key for blood pressure regulation, contrasting with subsequent steps.

Correct Answer: C

Rationale: Erythropoietin from kidneys boosts RBC production, not renin (pressure), aldosterone (sodium), or somatomedin (growth). This defines hematopoietic role, key for anemia, contrasting with RAAS hormones.

Correct Answer: C

Rationale: Peristalsis propels urine through ureters, not gravity (positional), hydrostatic (filtration), or osmotic (concentration). This defines ureteral motility, key for urine transport, contrasting with passive forces.

Correct Answer: B

Rationale: Renal corpuscle includes glomerulus and Bowman's capsule, not PCT, loop, or DCT (tubular). This defines filtration unit, key for GFR, contrasting with tubular segments.

Correct Answer: D

Rationale: Globin, albumin (proteins), and blood cells are too large for glomerular filtration all apply. This defines filtration barrier, critical for plasma selectivity, contrasting with small solutes.