Scientists have found that mars has water ice at its poles, even though volcanic activity has never been observed on mars. would this prevent the inside-out model from becoming a theory? a. yes, because any comet that hit earth also hit mars. b. yes, because it shows that volcanic activity is necessary for a planet to have liquid water. c. no, because no data from mars is applicable to earth. d. no, because a single observation is not sufficient to discredit a theory.