Question 15: the best answer seems to be Gatsby's determination and Daisy's weakness.
Gatsby was willing to do anything for Daisy, to the point of becoming a criminal just so that he could offer her a grand and rich life. Daisy, on the other hand, did not wait for Gatsby, but married Tom, a man whose love she did not have, but who could offer her the life Gatsby was unable to.
Question 16: the best answer is even though the people are guests in Gatsby's home, they know very little about him.
Gatsby opens his home to strangers by throwing gigantic parties. These people are not his friends, though. They've heard or come up with rumors about his life, his wealth, and the mysteries surrounding both. Gatsby's intent with such parties is to draw Daisy's attention and, perhaps, have her come over someday.
Question 17: the best answer seems to be the length and syntax reveal Gatsby's excitement and arousal about being in Daisy's large house.
Daisy's house seems to be a metaphor for what Daisy herself represents to Gatsby. From the length and syntax - but, mostly, from the adjectives used in this excerpt -, we can tell Gatsby is fascinated, even in a sexual way. The house is huge, it is alive, breathing. Its pulsating energy excites Gatsby.
Question 18: the best option is the storm adds an ominous mood to the scene signifying the characters Gatsby and Daisy are engaging in something forbidden.
It's as if nature is trying to show the fate of the affair between Gatsby and Daisy. If it were to be a happy ending, nature would have blessed it. It was cursed, however, by a storm. Gatsby and Daisy are pursuing a love that no longer exists, a reality they cannot have.
Question 19: the best answer is finding beauty in all situations.
"The Great Gatsby" has all the other themes present in it: degradation of society, the American Dream, and truth versus superficiality. It represents a society that values wealth and fun over true love and honesty. It's an America that chooses its heroes and points fingers in judgement of those who truly have a good heart.
Question 20: Daisy was driving Gatsby’s car, and when it struck Myrtle, Gatsby took over the drive home; he planned to take the blame for the accident.
Daisy was driving when Myrtle stepped in front of the car. She ends up running over her husband's lover, unknowingly. The episode, instead of bringing Daisy and Gatsby together, ruins their already difficult relationship. Tom is able to get his wife back by taking advantage of the stressful moment, as well as get rid of Gatsby by lying to his lover's husband about who actually killed Myrtle.