Oxygen is taken into the lungs.
Answer:
The excretory system is responsible for eleminating waste products and filtering body fluids.
It is b because it is tell you to recognize the problems
I am going to assume you are talking about emotion. If that is the case then it's better to let it all out, let the wall fall.
Decrease the intenseness of the stepper machine so his heart rate doesn't go over his target heart rate zone.