Answer:
The correct answer is "No, because a single observation on one planet is not sufficient to discredit a theory".
Step-by-step explanation:
A theory is a proposal that explains observable data often based on scientific information. A theory can be proved and can became a law, or a theory can be discredit. Either two outcomes need the generation and compilation of multiple observations and experiments. It is not possible to discredit a theory with a single observation. In this case, is not possible to discredit the inside-out model of Mars only by stating that volcanic activity has never been observed on Mars.