Courtship can be defined as the behavior used to obtain copulation with a partner, or to maintain reproductive interactions with an existing partner.Courtship, in animals, behaviour that results in mating and eventual reproduction. Courtship may be rather simple, involving a small number of chemical, visual, or auditory stimuli; or it may be a highly complex series of acts by two or more individuals, using several modes of communication.It help strengthen a pair bond that may last through the raising of the young or even longer.Courtship is its use as an isolating mechanism, a method of keeping different species from interbreeding.
Well, nitrogen is the gas that makes up 78% of the earth's atmosphere.
I would guess its in the air that we breathe. I am not really sure. Just basing this answer off of research.