Passage Summary: Some viruses are helpful, but they are so simple that a tiny change in their makeup can turn them into killers. Because nature constantly makes these kinds of changes through mutation, any virus is a potential threat.

Conclusion: Any virus has the potential to easily transform into a threat to humans.

Reasoning: Beneficial viruses are only a few atoms away from being deadly, and random mutations frequently cause changes of even greater complexity than that.

Analysis: For a 'Must be False' question, we are looking for a statement that flatly contradicts the rules established in the stimulus. The text states that a change of just a few atoms can make a virus deadly and that mutations of this scale are common. Therefore, any answer choice claiming that it is impossible for a beneficial virus to become dangerous, or that the necessary mutations never occur, would be the correct choice. We must find the statement that is logically incompatible with the idea that viruses are simple and easily altered into dangerous forms.