[MysteriousEd]

I have finals tomorrow and I don't get what he means by "Know the normal value of urine/serum osmolarity ratio and understand the meaning of an abnormal value and the conditions associated with them."

[Arkcon]

I don't see how you'll get the answer by tomorrow, except by checking your class notes.  This doesn't appear to be a typical Undergraduate Chemistry topic.  Maybe some medical science course, but I don't know which.