Answer:
Explanation:A mechanical wave requires an initial energy input. Once this initial energy is added, the wave travels through the medium until all its energy is transferred. In contrast, electromagnetic waves require no medium, but can still travel through one.
The UV rays could harm the DNA of skin cells. Skin cancers begin when the said harm affects the genes’ DNA which control the growth of the skin cell. There are three main types of UV rays, the first one is called UVA rays. They can damage the DNA of skin cells and age them. They are connected to long-term skin damage, however they are also thought to cause some skin cancers. The second one is called UVB rays, they have a little more energy than UVA rays. They are thought to cause most skin cancers as well. They can immediately damage the DNA of skin cells. The third one is called UVC rays, they have a greater amount of energy than the other types of UV rays, however they don’t usually cause skin cancer.
