Have you ever wonder or think before you breathed the air into your lung?
Yes, whenever you smell a fart, you are breathing in air that's been in someone elses butt. Your putting their butt air in your body.... Nasty huh?
It is an involuntary action. You don't have to think of it
You can monitor your inhaling and exhaling action voluntarily through the nose. However, you involuntarily breath air into your lungs. Most of the time you don't even notice you're breathing in and out.
Yes, you can control your breathing. There are breathing exercises that call for concentration and control of the breaths that you take in and let out. Although, it is an involuntary action as well.