Help please? what are the functions of a healthy kidney?

The following: Filters impurities from blood stream, nitrogenous waste from protein metabolism, blood urea nitrogen ; creatinine. Manages fluid/water balance in the body by first filtering ; reabsorbing as much as needed. More that is reabsorbed more concentrated urine becomes ; vice versa. Controls electrolyte balance of salt, potassium, chloride, acid ; base.Helps with BP control. Makes erythropoetin for rbcs.