What other organs are included in the respiratory system

Respiratory system
Nose.
Mouth.
Throat (pharynx)
Voice box (larynx)
Windpipe (trachea)
Large airways (bronchi)
Small airways (bronchioles)
Lungs.

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)

If it's a smaller child or infant, place one on the middle of the chest and on the child's back. (if it is a bigger child with enough room for two, place one on the upper right/your left of the chest, and one on the lower left/your right) the pads should never touch each other.