B2: Keeping Healthy Notes for the OCR GCSE Biology module: B2 – Keeping Healthy. These have been made according to the specification and cover all the relevant topics for examination in May/June. OCR GCSE B2 Notes: B2.1 How do our bodies resist infection? B2.2 What are vaccines and antibiotics and how do they work? B2.3 What factors increase the risk of heart disease? B2.4 How do our bodies keep a healthy water balance?