ans it carefully plz ----- as filtrate passes through the descending loop it is getting concentrated (how coz it is impermeable to electrolytes and permeable to water so more water is dere is shuld be diltue na ) and as it passes through the ascending limb it gets dilute (why coz now sollutes will be more it shuld be conc.) ................... xplain

Descending limb of loop of Henle is permeable to water and impermeable to electrolytes. The filtrate present in it has more water as compared to outside, so water moves out of the descending limb that concentrates the filtrate. Thus, basically water moves out of filtrate that concentrates the filtrate.

Ascending limb of loop of Henle is impermeable to water and permeable to electrolytes. The filtrate in it has more electrolytes, so electrolytes move out of the ascending limb that dilutes the filtrate. Thus, basically e moves out of filtrate that concentrates the filtrate.