Complete Prep for IGCSE Biology Configuration for independent learning 1. IGCSE Biology is classified into 20 topics and 88 sub-topics to organize concepts and questions. 2. Preparing for Concept Learning Memorization of main concepts will be induced through filling in the blanks. 3. Solving Past Papers of IGCSE Biology 1729 questions in Multiple Choice (paper 1 or 2) and Theory (paper 3or 4) Questions with correct answers. Topic. 11. Gas Exchange in Humans 01. Breathing System 02. Inhalation and Exhalation 03. Change of Air Composition 04. Exercise and Breathing Topic. 12. Respiration 01. Respiration Basics 02. Aerobic Respiration 03. Anaerobic Respiration Topic. 13. Excretion in Humans 01. Excretory System 02. Urinary System and Kidney 03. Function of Kidneys 04. Kidney Failure and Dialysis