Some smokers quit by gradually decreasing their dependence on nicotine.
a) stimulants
b) nicotine substitutes
c) inhalers. d) nicotine inhibitors

am i

organ system-an organ system is a group of organs that work together to perform one or more functions. each does a particular job in the body, and is made up of certain tissues.

when you breathe in, or inhale, your diaphragm contracts (tightens) and moves downward. this increases the space in your chest cavity, into which your lungs expand. the intercostal muscles between your ribs also enlarge the chest cavity. they contract to pull your rib cage both upward and outward when you inhale.