Wrong flaw. This assumes that because the first event has not occurred, the second event won’t either. The stimulus, in contrast, assumes that because the first event has occurred, the second event will.

This conclusion is more reasonable. This argument cites a condition (high snowfall) that has always led to an outcome (river overflow) and uses it to predict the same result. The stimulus, by contrast, cites an event that has only preceded the outcome, which allows for false positives.

Wrong flaw. This assumes that what’s been true of other planets is also true of Earth. The stimulus does not draw a conclusion about something outside the domain of its premises.

No flaw. This actually provides a sufficient condition. If introducing native species always results in extinctions, then it follows that the non-native species currently being introduced will result in extinctions. The stimulus is flawed because it cites a past pattern rather than a proper sufficient condition.

This assumes that a past patterns will continue to hold in the future, and it fails to account for false positives—instances where high infection rates among animals were not followed by human outbreaks. Given that such false positives could be common, the conclusion is unsupported.