Answer to Question 1
Sun lamps and tanning parlors provide mainly ultraviolet A (UVA) rays. Once thought to be safe, they are now known to be damaging and have been linked to melanoma. As little as 15 to 30 minutes of exposure to UVA rays can be as dangerous as a day spent in the sun. Similar to regular exposure to sunlight, short-term exposure to recreational tanning at a salon causes DNA alterations that can lead to skin cancer.
Answer to Question 2
When nuclei lose their ability to regulate and control cell growth, cell division is disrupted and mutant cells can develop. Some of these cells might grow uncontrollably and abnormally, forming a mass of tissue called a tumor, which can be either benign or malignant. Benign tumors do not invade other tissues. Although they can interfere with normal bodily functions, they rarely cause death. A malignant tumor is a cancer. Cancer is not a single disease, but rather a category of diseases that share similar traits including gene mutation and uncontrolled cell growth. More than 100 types of cancer can develop in any tissue or organ of the human body.
