I think the best response to this question would be
D. speak your mind
Ibeleive the answer is bullying because younger kids get bullied and even sometimes adults but teenegers get bullied the most by other teenagers which causes stress and other issues.
sorry if its wrong
Intensity, how hard a person exercises. The speed or workload used in a given exercise period.
Gradually increasing duration and intensity of activity is formally referred to as progression.
Hoped I helped!
Joe gets a tax rebate fir donating to a charity