This free course was written by Allan Cochrane.
Except for third party materials and otherwise stated (see terms and conditions [Tip: hold Ctrl and click a link to open it in a new tab. (Hide tip)] ) and referenced in the course and in the acknowledgements section, this content is made available under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 Licence.
The material acknowledged below is Proprietary and used under licence (not subject to Creative Commons Licence). Grateful acknowledgement is made to the following sources for permission to reproduce material in this free course:
Figure 1: David Novi/123rf
Figure 2: dynasoar/Getty Images
Figure 3a: Peter Reimann https://www.gazettelive.co.uk/ news/ teesside-news/ teesdale-wilderness-park-set-facelift-7654000
Figure 3b: Mike Kipling Photography/Alamy Stock Photo
Every effort has been made to contact copyright owners. If any have been inadvertently overlooked, the publishers will be pleased to make the necessary arrangements at the first opportunity.
Don't miss out
If reading this text has inspired you to learn more, you may be interested in joining the millions of people who discover our free learning resources and qualifications by visiting The Open University – www.open.edu/ openlearn/ free-courses.