Hint:Henle loop, a long U-shaped segment of the tubule. The key feature of Henle 's loop is to recover urine from water and sodium chloride.
Inside each nephron of the kidney of reptiles, birds , and mammals, it conducts urine. This feature facilitates urine output that is much more concentrated than blood, reducing the amount of water necessary for survival intake.For many animals that live in arid environments such as deserts, Henle's loops are highly successful.
The Henle loop can be divided into three main segments anatomically: the thin descending limb, the thin ascending limb, and the thick ascending limb (sometimes referred to as the diluting segment). The liquid entering the Henle loop is the solution of salt, urea, and other substances passing through the proximal convoluted tubule, from which the body requires most of the dissolved components.
The first portion of the loop, the thin descending limb, is water-permeable, and the liquid that reaches the bend of the loop is much richer in salt and urea than blood plasma.Sodium chloride diffuses out of the tubule into the surrounding tissue, where its concentration is lower, as the liquid returns through the thin ascending extremity.
In the third segment of the circle, the thick ascending limb, the tubular wall can, if necessary, in an active-transport process requiring energy expenditure, have the effect of further salt removal, even against the gradient of concentration.
Thus the correct answer is option (D) Nephron.
Note:The reabsorption of salt from the urine in a healthy person precisely maintains the body 's requirement: virtually none is allowed to escape into the urine during periods of low salt intake, but the excess is excreted during periods of high salt intake.