Identify the mechanisms of water output.

Correct Answer: C

Rationale: Water output is exhaled air (lungs), sweat (skin), urine (kidneys), feces (intestines) e.g., ~1.8 L urine, 0.5 L sweat daily. Inhaled air gains water opposite. Including inhaled misdirects input not output. Excluding any (sweat, feces) omits key routes wrong. Four outputs distinguish it, critical for water loss, unlike input or partial lists.

Correct Answer: A

Rationale: Hyperventilation rids excess H blows off COâ‚‚, raising pH (e.g., respiratory alkalosis). Hypoventilation retains COâ‚‚ worsens. Urination is slow kidneys lag. Holding breath increases COâ‚‚ opposite. Hyperventilation's speed distinguishes it, key to acute pH correction, unlike retention or slow methods.

Correct Answer: B

Rationale: Urea is produced in the liver protein breakdown via urea cycle (e.g., ammonia detox). Muscles produce creatinine not urea. Kidneys excrete not synthesize. Spleen is immune not metabolic. Liver's production distinguishes it, key to nitrogen handling, unlike muscle, kidney, or spleen roles.

Correct Answer: B

Rationale: Glucose reabsorption occurs fully in proximal tubules e.g., SGLT transporters reclaim all (~180 g/day). Insulin aids uptake not tubular reabsorption. Metabolism doesn't vary it threshold fixed. Liver regulates blood glucose not tubules. PCT's complete reabsorption distinguishes it, critical for glucose retention, unlike hormonal or metabolic control.

Correct Answer: B

Rationale: Ammonia (NH₃) is a nitrogenous waste e.g., distal tubule buffers H . Amino acids are reabsorbed not excreted. HNO₃⁻ (nitrate) isn't physiological false. Thionitrate isn't a compound nonsense. NH₃'s waste role distinguishes it, key to nitrogen excretion, unlike conserved or fictitious options.