Akey factor in the level of danger presented by a tumor is answer
a. nondisjunction
b. contact inhibition
c. monosomy
d. the presence of oncogenes e. phase of cell division

The answer is D. The presence of oncogenes

Oncogenes is a gene that has potential to cause Cancer. Once it appear on tumor cells, Oncogenes often mutated at a very high level. When the cells critical function altered, they usually undergo a rapid cell death. But once oncogenes activated, those malfunction cells will not undergo rapid cell death, filling our body with malfunctioning cells

C.1960s and 1970s hope it's right