(3) 2.1 2.2 23 Provide labels for structures A, B and State THREE functions of D Fertilisation usually takes place at Y. Why wil a blockage at X 2.3.1 Prevent fertilisation at Y 2.3.2 Not necessarily lead to infertity (2) 3. Study the graph below which shows the menstrual cycle and the influence of the different hormones on it.