This Is a Certified Answer

Certified answers contain reliable, trustworthy information vouched for by a hand-picked team of experts. Brainly has millions of high quality answers, all of them carefully moderated by our most trusted community members, but certified answers are the finest of the finest.
In nitrogen cycle, a gaseous nitrogen must be converted to a chemically usable form before it can be used by living organism. in order to be converted to ammonia and nitrates. first nitrogen enters the soil and becomes part of living organisms.  proteins are obtained from amino acids. it is  very essential for us, humans and animals get their nitrogen (proteins) by consuming plant and animals.