Unlike other cancers, the vast majority of skin cancers have no potential to spread to other parts of the body (metastasize) and become life-threatening. There are two major types of skin cancer: basal cell carcinoma (the most common) and squamous cell carcinoma (the second most common). Melanoma is also a form of skin cancer but is far less common, though more dangerous, than the other two varieties.
The definition of backfill is material used to refill a hole, usually what was previously dug out of the hole. Dirt and gravel are examples of backfill. Backfill is defined as to return soil and other materials to a hole after it was dug.
A landfill site (also known as a tip, dump, rubbish dump, garbage dump or dumping ground and historically as a midden[1]) is a site for the disposal of waste materials by burial and the oldest form of waste treatment (although the burial part is modern; historically, refuse was just left in piles or thrown into pits).