Parts indicated by the guidelines 1 to 8 are as follows:
1. Afferent arteriole from renal artery;
2. Efferent arteriole
3. Bowman’s capsule,
4. Glomerulus;
5. Proximal convoluted tubule with blood capillaries;
6. Distal convoluted tubule with blood capillaries;
7. Collecting tubule;
8. U-shaped loop of Henle.
Study the diagram and answer the questions that follow:
(c) Which structure contains the highest concentration of urea?