What does mournful influence mean?

teenagers are certainly stereotyped as moody.

most people view teenagers as naturally moody and grumpy, even when this is wrong. many teens are suffering from depression but it is brushed off as "just a phase" or "that's just cause they're a teenager"

the personification of the word prudence d) it effectively enhances the logos and ethos of the argument.

logos means appeal to the logic or reasoning of the people.

ethos means appeal to the credibility of the argument, that it is worth listening to and acting upon.