Grant Castaneda, I tutored a middle school student in math for a year teaching him all of the curriculum for Algebra 2 at University of California, San Diego, Numerade Educator

01:10

Campbell Biology

The high osmolarity of the renal medulla is maintained by all of the following except
\begin{equation}\begin{array}{l}{\text { (A) active transport of salt from the upper region of the }} \\ {\text { ascending limb. }} \\ {\text { (B) the spatial arrangement of juxtamedullary nephrons. }} \\ {\text { (C) diffusion of urea from the collecting duct. }} \\ {\text { (D) diffusion of salt from the descending limb of the loop }} \\ {\text { of Henle. }}\end{array}\end{equation}

Chapter 44: Osmoregulation and Excretion