18.
Why is excretion important in order to achieve osmotic balance?
19.
Why do electrolyte ions move across membranes by active transport?
20.
Why are the loop of Henle and vasa recta important for the formation of concentrated urine?
21.
Describe the structure of the kidney.
22.
Why might specialized organs have evolved for excretion of wastes?
23.
Explain two different excretory systems other than the kidneys.
24.
In terms of evolution, why might the urea cycle have evolved in organisms?
25.
Compare and contrast the formation of urea and uric acid.
26.
Describe how hormones regulate blood pressure, blood volume, and kidney function.
27.
How does the renin-angiotensin-aldosterone mechanism function? Why is it controlled by the kidneys?