The average time to death from starvation in a fruit fly is about 20 hours. selecting for increased starvation resistance in fruit flies: a. can produce populations in which the average time to death from starvation is 160 hours. b. has no effect because it is too complex a physiological process, dependent upon the effects of too many genes. c. has little effect because constant mutation reduces starvation resistance, counteracting any benefits from selection. d. has no effect because it is not a trait that influences fruit fly fitness. e. can double this, at which point the genetic variation for this trait is exhausted.