Sodium balance is controlled by:

Correct Answer: A

Rationale: Sodium balance hinges on GFR (filtration rate) and Na reabsorption e.g., PCT (65%), aldosterone (distal). GFR/renin ties BP not direct Na . Na /K links aldosterone partial view. None denies control false. GFR/reabsorption synergy distinguishes it, critical for Na homeostasis, unlike partial or null options.

Correct Answer: C

Rationale: Collecting ducts set urine osmolality ADH aquaporins adjust (e.g., 50-1200 mOsm). Water secretion is false reabsorbed. Most reabsorption is PCT (~65%) not collecting. ADH increases permeability opposite. Osmolality control distinguishes it, critical for concentration, unlike secretion or misattributed roles.

Correct Answer: A

Rationale: ADH is synthesized in the hypothalamus e.g., supraoptic nuclei, released by pituitary for water retention. JG cells secrete renin not ADH. Tube is ureter unrelated. Micturition is urination not hormone. Hypothalamic synthesis distinguishes it, critical for osmoregulation, unlike renal or action terms.

Correct Answer: A

Rationale: Micturition is the act of passing urine e.g., bladder emptying reflex. Vasa recta is capillaries not action. Zona glomerulosa secretes aldosterone not voiding. Macula densa is JGA not urination. Voiding process distinguishes it, critical for excretion, unlike structures or secretions.