What is the definition of biotic reservoir and what is the definition of density of water?

Biotic reservoir - nitrogen used in many molecules especially in proteins and nucleic acids (DNA) Nitrogen fixation - converts nitrogen gas into ammonia.

not sure if this is what you'r looking for nnew= nold

the sun creates it's own light, also gives light and life to bunch of stuff like plants,animals,humans etc.photosyntesis is the process of making food which needs sun,water,nutrients etc.