The distal convoluted tubules of the kidney

Correct Answer: A

Rationale: Distal convoluted tubules (DCT) are simple cuboidal not brush border (PCT), lacking basement (false), or RER-rich (mitochondria-rich). This defines DCT structure, critical for fine-tuning, contrasting with PCT features.

Correct Answer: B

Rationale: Lacis cells are extra-glomerular mesangial cells in the JGA not secretory, intra-glomerular, or neuroepithelial. This specifies their identity, key for JGA support, contrasting with other cell types.

Correct Answer: B

Rationale: Renin is from afferent not efferent arterioles; other pairs (macula/DCT, fenestrae/glomerulus, collecting/ray) are correct. This corrects renin source, key for RAAS, contrasting with true associations.

Correct Answer: C

Rationale: Macula densa has basal Golgi not PCT (brush), DCT (no brush), or efferent (renin in afferent). This identifies correct pair, key for histology, contrasting with misassociations.

Correct Answer: C

Rationale: Arcuate arteries supply interlobular arteries not afferent (next), efferent (post-glomerular), interlobar (prior), or stellate (cortical veins). This repeats Q29, key for flow, contrasting with missteps.