Cancer is feared by everyone. And there is more and more fear about cancer. Not the disease itself -- there is no such thing as a high incidence rates  of cancer. Except for lung cancer, mostly caused by cigarette smoking, the incidence rates are not on the rise. However, some kinds of cancer are decreasing. But the fear of cancer is catching, and the country stands at risk of an anxiety. The earth itself is coming to seem like a huge carcinogen . The ordinary, more or less, scientific statement that something between 80 and 90 percent of all cancers are due to things in the environment is taken to mean that none of us will be safe until the whole environment is "cleaned up." This is not at all the meaning. The 80-percent calculation is based on the unthinkable differences in the incidence of cancer in various societies around the world -- for example, the high incidence of liver cancer in Africa and the Far East, stomach cancer in Japan, breast cancer in Western Europe and North America, and the relatively low figures for breast cancer in Japan and parts of Africa and for liver cancer in America. These data show there may be specific environmental influences, but largely based on personal life-style, which determines the incidence of various forms of cancer in different communities -- that is all the data suggest. The overall incidence of cancer, counting up all the cases, is probable roughly the same everywhere. According to the passage, the incidence of cancer is generally believed   _  .
to be based on inactive life style to be due to anxiety to result from environmental influences to be caused by heavy smoking