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The sun gives off many different types of rays - cosmic, gamma, ultraviolet, visible and infra-red
, but only those reaching the surface of the Earth - ultraviolet, visible and infra-red rays - have any known effect on skin cells. The effects of exposure to the solar rays have been studied in detail and show that their beneficial effects should not lead us to forget their potential harmfulness. It is therefore essential to be adequately protected.
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