Oh wow, no ones answered already! Sorry for being so late then
I've been on camp for around 5 days now and still am at camp. Anyways, i'll attempt to help you out with this question.
Okay... so what are kidneys?
A kidney is an organ in the body that is responsible for many homeostatic functions as well as are essential in the urinary system. The kidneys have
different functions than the liver, I won't go into detail, but this is the key difference.
What is this "liver" you talk of??!!1
The liver is an organ that plays a role in things such as digestion (via the production of bile), the actual process of deamination is different to the process of filtering that occurs in the kidney and lastly but obviously, both are in different forms/structures.
To sum up;
They differ in function, structure and location.
More info @
http://www.gruts.com/misc/faq/liver-kidneys/
Good Luck!