relationship between humans and plants

all species develop relationships through their life-spans.
mother-child, husband-wife, etc, etc are the easy ones among all known species (except the asexual organisms).

adding humans into the animal kingdom, there is a very interesting connection between animals and plants, which superimposes and supercedes all relationships.
this was posed to us by this most remarkable naturalist/humanist - deepak suchde (yes, the bearded gentleman) as "what is this relationship?"

this is the relationship of breaths.
the exhalation (उच्छ्श्वस) of plants is our inhalation (श्वास) and vice versa.
no other relationship can be so intricate.

i am still staggering.