The protein attaches to the host ACE2 receptor and then promotes fusion of the host membrane with the envelop of the viral particle.

what's the question ?

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.

geographic isolation