Normal cells may undergo changes during cell processes that can lead to
cancer. however, most of them do not form cancers.
which of the following explanations accounts for the relatively low rates
of cancer?

a. cancerous cells die when they are exposed to radiation.
b. cancerous cells are crowded out by normal cell growth.
c. cancer cells grow only very slowly at first.
d. dna repair systems fix the mutation before it causes cancer.