What is the difference between a pathogen and an antigen

Antigen is a molecule capable of causing the immune system to produce antibodies against it. Pathogen is an infectious agent that may cause a disease.

Explanation:

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.