American Cancer Society. While skin cancer is the most prevalent form of cancer, with over 1,000,000 diagnosed cases in the U.S. each year, the good news is that it usually can be prevented by avoiding exposure to bad ultraviolet light of the sun. Explains the difference between UVA ultraviolet rays (which can cause wrinkles and aging) and UVB ultraviolet rays (which can cause skin cancer). Provides a checklist of conditions that make people more prone to sun damage, making it all the more important to avoid exposure to ultraviolet rays. Explains in detail how to protect yourself and your loved ones from damaging ultraviolet rays.