The OCR GCSE Biology Paper 4 (November 2021) examines topics like decomposition, trophic levels, and genetic inheritance. Key areas include the carbon cycle, antibiotic resistance, and the use of monoclonal antibodies. The paper explores practical applications, including population sampling, field investigations, and experiments on sulfur dioxide′s effects on photosynthesis. It emphasizes data analysis, experimental design, and concepts like genetic engineering, CJD inheritance, and cancer treatments. Ethical considerations and the application of biological principles in conservation, agriculture, and health are central themes.