Document C
"The part of cancer prevention we know the most about is the avoidance of carcinogens that induce or promote cancer. Carcinogens may alter normal growth- promoting genes (proto-oncogenes), to make them permanently turned on.
Carcinogens may also damage growth-suppression genes (tumnor suppressors) such
that the genes become permanently turned off. Both gene changes may be
necessary to create cancer. Since prolonged exposure to carcinogens is one of
necessary ingredients for cancer, prevention of cancer in the elderly must begin
before people become old

1. Identify one carcinogen or activity that people can avoid to help prevent cancer
"before people become old"
2. Identify one change in the cell cycle if growth-promoting genes are permanently
turned onIdentify one carcinogen or activity that people can avoid to help prevent cancer "before people become old"