A biologist observes that some cells are growing faster than others in a tissue culture. a week later, the scientist notices that the fast- growing cells have tripled in number.This observation is a possible clue that the fast- growing cells-
a. have killed the slow-growing cells
b. were exposed to antibiotics or chemical
c. contain an unknown enzyme
d. have disruptions in their normal cell cycle
Answer: d. have disruptions in their normal cell cycle