Which is not a factor that affects teenagers' ability to resist peer pressure and stand up for their own values? how high or low their self-esteem is the nature of their family background the number of friends they have the role models they look up to

I would say nature of their family background is the least likely to affect their ability to resist peer pressure but I don't think that it has no influence at all 

I'm not ment for this question

The person who utilize the progression principle will keep adding the difficulty of the exercise that he's doing, while the person who does not, will only stay stagnant.  the person that utilize progression principle, will get a stronger endurance because now his body is conditioned to do harsher routines.{the answer was already on verified)