Where does tubular reabsorption primarily occur?

Correct Answer: D

Rationale: Tubular reabsorption primarily occurs in the PCT ~65-70% of filtrate (e.g., Na , water, glucose). Collecting duct adjusts less volume. Distal tubule fine-tunes smaller role. Capsule filters not reabsorbs. PCT's dominance distinguishes it, critical for bulk reclamation, unlike later or filtration sites.

Correct Answer: C

Rationale: The JGA is between afferent arteriole and distal tubule macula densa/JG cells (e.g., renin release site). Loop is tubular not vascular. Medulla oblongata is brain unrelated. Collecting/PCT lacks JGA wrong. JGA's position distinguishes it, critical for GFR/BP control, unlike tubular or brain errors.

Correct Answer: B

Rationale: Urine is ~95% water rest solutes (e.g., urea, ions ~5%). 100% ignores solutes false. 90% underestimates water too low. 85% overestimates solutes incorrect. 95% distinguishes it, critical for urine composition, unlike absolute or skewed estimates.

Correct Answer: D

Rationale: Skeletal system isn't directly influenced by kidneys bones respond indirectly via vitamin D (e.g., calcium). Cardiovascular is BP/volume direct. Respiratory ties to pH HCO₃⁻ effect. Endocrine involves hormones (renin) direct. Skeletal's indirect link distinguishes it, critical for system specificity, unlike directly impacted systems.

Correct Answer: A

Rationale: Glomerular capillaries have larger pores fenestrated (e.g., allow plasma filtration, not cells/proteins). Shorter length is false longer for GFR. Innervation is minimal not functional trait. Na absorption is tubular not glomerular. Pore size distinguishes it, key to filtration selectivity, unlike length, nerve, or absorption traits.