An antibiotic is over-prescribed and so used by too many people, Some people stop taking the antibiotic when they begin to feel better, and so do not complete the course, A random change in a bacterium makes a strain that is resistant to the antibiotic, The antibiotic kills the non-resistant bacteria but leaves the resistant strain to multiply and spread, When someone is infected with the resistant strain they cannot be cured by the antibiotic Plants take up carbon dioxide from the atmosphere during the process of PHOTOSYNTHESIS Carbon locked in the ground is released back into the atmosphere by BURNING P2 Radiation and life • What do we know about the Earth and space? • How have the Earth’s continents moved, and with what consequences? • What is known about stars and galaxies?
• How do scientists develop explanations of the Earth and space? B2 Keeping healthy • How do our bodies resist infection? • What are vaccines and how do they work? • What are antibiotics, and why can they become less effective? How are new drugs developed and tested? • What factors increase the risk of heart disease? C2 Material choices • What different properties do different materials have? • Why is crude oil important as a source of new materials such as plastics and fibres? • Why does it help to know about the molecular structure of materials such as plastics or fibres? • When buying a product, what else should we consider besides its cost and how well it does its job? How should we manage the wastes that arise from our use of materials?