But that is not how it works.. According to Spencer, an SPF 15 product blocks about 94% of UVB rays; an SPF 30 product blocks 97% of UVB rays; and an SPF 45 product blocks about 98% of rays. After that, it just gets silly, he says.Sunscreens with higher SPF ratings block slightly more UVB rays, but none offers 100% protection.he SPF rating is a measure of the time it would take you to sunburn if you were not wearing sunscreen as opposed to the time it would take with sunscreen on. SPF is not a consumer-friendly number, says Florida dermatologist James M. Spencer, MD.
Definition of cancer - a disease caused by an uncontrolled division of abnormal cells in a part of the body Definition of cancer - a disease caused by an uncontrolled division of abnormal cells in a part of the body
Leukemia (lo-KEY-me-a) is a type of cancer in which the body produces a large number of immature, abnormally shaped blood cells. It usually affects the white blood cells, or leukocytes (LOO-ko-sites), which help the body fight infections and other diseases. for searching the Internet and other reference sources.