The OCR GCSE Biology Paper 4 (June 2019) covers photosynthesis, enzyme activity, and human health. Key topics include plastic pollution, microplastics in food chains, and antibiotic resistance. Practical investigations examine the effects of temperature on photosynthesis, stomatal density, and risk reduction in microscopy. Human biology concepts include smoking’s link to cancer, stem cell function, and sickle-cell disease in malaria regions. Ethical and environmental considerations, data interpretation, and experimental design are emphasized, alongside real-world applications in biodiversity, conservation, and public health.