Students who fall behind in their school work will never be able to get jobs and will end up living with their parents forever. the flawed logic in this statement is an example of

This should be a slippery slope logical fallacy.

That's when you start with a thing and swiftly move on to the consequences that may come from that thing and are usually negative. Here you have the slippery slope that if you don't do your homework, you are bound to fail and end up being a failure while it is not so in reality.

The details that best show evidence of tribal traditions are, "never in the history of his people had a man married a woman who spoke a different tongue” and "it has never been heard," was the verdict of an old man speaking a few weeks later.