This free course was written by Katharine Reedy, Natasha Huckle and Wendy Mears and first published in 2016. It was partly updated in 2020 by Sue Lowe.
Except for third party materials and otherwise stated (see Creative Commons Attribution-NonCommercial-ShareAlike 4.0 Licence.), this content is made available under a
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Figures 1, 2: Derived from: http://www.tagxedo.com and licensed under a https://creativecommons.org/ licenses/ by-nc-sa/ 3.0/
Figure 3: National Park Service. Photo: D W Peterson in Flickr https://creativecommons.org/ licenses/ by/ 2.0/
Figure 4: ©anafcsousa/iStockphoto.com
Figure 5: iStockphoto.com
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