This free course was written by Tom Redshaw, Bedford College Group using materials belonging to The Open School Trust Ltd. (trading as the National Extension College), in partnership with Middlesbrough College, West Herts College and The Open University and in collaboration with Coleg Cambria, Adult Learning Wales, Coleg Gwent and the NPTC Group of Colleges. Copyright in this material belongs to The Open University, 2019.
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219680: Figure 1 bottom left: © michael spring / 123 Royalty Free
219600: Figure 1 bottom right: © SolStock / istock / Premium Images Plus
219598: Figure 1 top left: © Katarzyna Bialasiewicz / 123 Royalty Free
219597: Figure 1 top right: © Bernard Bodo / 123 Royalty Free
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