most skin cancers are caused by too much exposure to the sun's ultravolet uv rays.the two types of uv rays that cause melanoma are uv-a and uv-b rays hope it helps :)
The sun is very damaging to the skin. The ultra violent rays will kill your skin after a while, overexposure to the suns rays can cause this. P.S. studying to go into the medical field this is how I know. Hope this helps! ;)