The OCR GCSE Biology Paper 3 (November 2020) explores cardiovascular systems, population changes in endangered species, and genetic engineering. Key topics include the human circulatory system, deforestation, pathogen spread in plants, and photosynthesis rates. Practical investigations address enzyme activity and light microscopy techniques. The paper emphasizes data analysis, experimental design, and real-world applications in disease prevention, conservation, and food security. Ethical considerations surrounding genetically modified crops and conservation efforts are highlighted, alongside core biological concepts such as energy transfer and genetic inheritance.