There is a pair of Bean shaped organs ' P 'in human body towards the back , just above the waist. A waste product Q formed by the decomposition of unused protein in the liver is brought into organs P through the Blood. The numerous tiny filters R are present inside the organs P clean the dirty blood by removing the waste product Q. if due to some reason, the organ P of a person stop functioning completely, the person's blood can be cleaned periodically by process S so as to save his life what are P, Q, R and S? pls don't give irrelevant answers ​