Hey there,
Your question states: Which is a function of the kidneys?
They help contribute and waste the extra fluids and also the grease and the waste so to speak and they also take out the urine and just about like 1 through 2 quarts of that. They also regulate 120 to I think 140-150 quart's of blood about So based from your options, your correct answer would be D.)to regulate blood volume.
To clarify your answer, your correct answer would be [tex]\boxed{D}[/tex]
Hope this helps.
~Jurgen
