Aside from the extreme temperatures found in the tundra, the lack of precipitation is quite extreme; with only 6 to 10 inches of rain or snow per year, the tundra is as dry as the driest desert.
mutations cause most cases of cancer. Some acquired mutations can be caused by things that we are exposed to in our environment, including cigarette smoke, radiation, hormones, and diet. Other mutations have no clear cause, and seem to occur randomly as the cells divide.
