Vary from person to person!
I researched and I believe the answer is both 2 and 4.
cool downs affect your body by 1 stretching everything after the work out 2 prevent you from hurting yourself 3 help you stay in shape so you can work out more. Warm ups help you with 1 stretching your muscles so you don't get hurt 2 stop you from breaking something 3 helps get your joints into place.
It may help you get fit. Lifting weights, running or spending 45 sweaty minutes on the exercise bike are all forms of stress on your body. But it's good stress.
