Exposure to ultraviolet (UV) radiation is a major risk factor for most skin cancers. Sunlight is the main source of UV rays. Tanning lamps and beds are also sources of UV rays. People who get a lot of UV exposure from these sources are at greater risk for skin cancer.V rays damage the DNA of skin cells. Skin cancers start when this damage affects the DNA of genes that control skin cell growth. There are 3 main types of UV rays: 1  UVA rays age skin cells and can damage their DNA.
Northern Africa. The Sahara is the largest desert in the world and occupies approximately 10 percent of the African Continent. The ecoregion includes the hyper-arid central portion of the Sahara where rainfall is minimal and sporadic. Although species richness and endemism are low, some highly adapted species do survive with notable adaptations.
Northern Africa Weather Overview The region of North Africa comprises of Western Sahara and the countries: Morocco, Algeria, Tunisia, Libya, Egypt and the Sudan. North Africa is predominantly desert with narrow bands of semi-arid and milder, Mediterranean climates near the Mediterranean coast, north of the Atlas Mountains which stretch from Morocco to Tunisia.