The nouns are president, class, and class officials. hope this helps !
Flawless means without faults
The answer is number 4) These numbers show that teenagers care about others.
Sentences 1-3 show evidence to support the main argument, which is that teenagers help others. Sentence 1 gives an individual example, and on sentences 2 and 3, it presents statistical data.
APA style you can never go wrong