13. The following structures are part of the nephron. In which of these structures is water re-absorbed?

I. Proximal Tubule
II. Distal Tubule
III. Descending limb of the loop of henle
IV. Ascending limb of the loop of henle
V. Collecting duct

Water re-absorption mainly occurs in the Proximal Tubule, Descending limb of the loop of Henle, and the Collecting duct.