Both Earth and the planet Venus have a large amount of water vapor in the atmosphere, and have extensive volcanic activity throughout history. Does this observation support or disprove the inside-out model? Supports, because Venus is near Earth and would have been hit by all the same comets. Disproves, because a single observation can discredit a theory. Disproves, because data taken on Venus is not applicable to Earth. Supports, because it shows that volcanic activity may be related to water vapor.