In respiration, gases move in and out of

Your lungs

Explanation:

One of the principal puts that attendants separated themselves was the front line.  

Explanation:

the field or ground on which a fight is battled. a territory of dispute, strife, or threatening resistance: During that period the classroom turned into a combat zone of in congruent ideologies.a put where a fight is being battled or has been battled before: They conveyed the injured from the front line. a Civil War front line.