Which of the following pairs of structures are the most similar in function?
A. Distal convoluted tubule and collecting duct.
B. Proximal convoluted tubule and distal convoluted tubule.
C. Distal convoluted tubule and ascending limb of the loop of Henle.
D. Ascending limb and descending limb of the loop of Henle.
Answer: A. Distal convoluted tubule and collecting duct.