1) Warm up and stretching activities
2) Endurance training
3) Cool-down and stretching activities
4) Flexibility training
5) Resistance training
6) Recreational activities.
To evaluate how your actions affect your health, you would use the life skill of making healthy decisions (d).
Answer:
Because, as an adult, they might have more experience dealing with that problem or they might know who to call or what to do. As a teenager, you have a very limited and short experience with the world and you might not always have the right idea about how to do something or any ideas at all. Plus, that's just what adults do.
They could encourage you to be better and make you work harder, or they could be abusive and put you down worsening your mental state.
Sit-ups I hear is hard on the back, I don't think people like these now a days.
Leg extensions as apposed to squats for quads I've heard about being bad for knees as well.