When cells leave the cell cycle, they exit during g1 phase and then enter g0 phase, a resting period. most normal cells can leave g0 phase and reenter the cell cycle at g1 phase before entering s phase. cancer cells are different because they cannot enter g0 phase and are likely to do which of the following? a) fall to complete s phase b) mutate during g1 phase c) repeat the cell cycle continuously d) die after completing mitosis