What does "these" refer to

Which number is main idea? i need answer quick. (1) people may think that love and romantic feelings are enough of a basis for choosing a spouse. (2) the chances of a marriage surviving, however, would improve if prospective marriage partners considered a few unromantic questions before deciding on matrimony. (3) for example, do the two individuals involved share a common socioeconomic background? (4) the more similar they are in their social, economic, religious, and cultural backgrounds, the more similar their expectations about married life will be. (5) in addition, what are their goals? (6) it’s a big advantage to the marriage if they know and share one another’s goals concerning career, lifestyle, and family. (7) finally, and maybe most important, how does the prospective spouse treat others in his or her life? (8) during the courtship, the boyfriend or girlfriend may get special consideration, but in the long run, spouses will probably treat each other about the same way they treat their own family members.

Which of these is not a function of shock absorbers?

Susie ran a race. she ran 55 miles an hour, and the race took her tt hours to complete.