In which section of the nephron does the filtrate have a higher osmolarity than the blood when it enters and lower osmolarity than the blood when it leaves?

I believe it is the ascending loop of henle. In the ascending portion, the loop becomes impermeable to water and instead the cells of the loop, actively reabsorb the solute; thus water is not reabsorbed but ions are readily reabsorbed. As the ions are reabsorbed the concentration becomes more and more hypotonic until it reaches 100-150 mOsm/L. Therefore, the ascending loop is called the diluting segment of the nephron due to its ability to dilute the fluid in the loop from 1200 to 100 mOsm/L.

The truman doctrine was an american foreign policy whose stated purpose was to counter soviet geopolitical expansion during the cold war. it was announced to congress by president harry s. truman on march 12, 1947, and further developed on july 12, 1948, when he pledged to contain threats to greece and turkey