Excretion - Theory & Question Answers - Biology IX Excretion - Theory & Question Answers - Biology IX Theory & Question Answers Chapter No. 12 "Excretion" Practical Centre for class IX, 9th, Ninth Class Practical Centre Biology ninth class Theory & Question Answers from Excretion Excretion Chapter List | Theory & Question Answers | Fill In The Blanks | MCQs | Online MCQs