Final answer:
The specialized vascular structure in the renal medulla that controls and maintains the balance of solute and water reabsorption is the 2) Loop of Henle.
Step-by-step explanation:
The specialized vascular structure in the renal medulla that controls and maintains the balance of solute and water reabsorption is the Loop of Henle. The Loop of Henle consists of two sections: the thick and thin descending limb and the thin and thick ascending limb. These sections are highly specialized to enable the recovery of sodium and water that were filtered by the glomerulus. The Loop of Henle plays a crucial role in the formation of concentrated urine by facilitating the exchange of solutes and water with the renal medulla.