____ radiation (UV) is a high-energy form of light, present in ____. Exposure to UV light can result in molecules gaining sufficient ____ for bonds to be ____. This is the process responsible for ____ and also contributes to ____ of the skin. Sun-block products ____ UV light reaching the skin.     When UV light breaks bonds, ____ ____ are formed. These have unpaired ____ and, as a result, are ____ ____. Free radical chain reactions include the following steps: initiation, ____ and termination.      Many ____ products contain free radical ____; molecules which can react with free radicals to form ____ molecules and prevent chain reactions. Free radical scavengers are also added to ____ products and to ____.

Skin Care

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