Which is found in the highest concentration in the urine?

Correct Answer: B

Rationale: Urea is the most concentrated waste in urine not uric acid, glucose (reabsorbed), or creatinine (less). This identifies excretory priority, critical for nitrogen, contrasting with reabsorbed solutes.

Correct Answer: C

Rationale: Liver on right displaces right kidney not heart, size differences. This explains asymmetry, key for anatomy, contrasting with organ size myths.

Correct Answer: C

Rationale: Nephrons filter/form urine not hilum (entry), neurons (nerve), or medulla (region). This defines functional unit, key for physiology, contrasting with structural terms.

Correct Answer: B

Rationale: Glomerular filtrate has much less protein than plasma filtration membrane (e.g., podocytes, basement) excludes large proteins (e.g., albumin), unlike plasma's ~7 g/dL. Glucose is present reabsorbed later. Sodium levels are similar freely filtered. More proteins would defy filtration incorrect. Lower protein content distinguishes it, key to filtrate's composition, unlike glucose or sodium errors.

Correct Answer: B

Rationale: Sodium is mostly reabsorbed by primary active transport Na /K -ATPase pumps it from tubular cells to blood (e.g., PCT ~65%). Passive diffusion occurs minimally gradient-driven. Secondary active transport aids co-transport (e.g., glucose) not primary. Facilitated diffusion lacks energy insufficient. Active pumping distinguishes it, key to sodium gradient creation, unlike passive or co-transport mechanisms.