why do all organisms need nitrogen?

For amino acids and nucleic acids.

Organisms are made up of very large molecules which themselves are composed of repeating sequences of smaller molecules all linked together. These large molecules are known as polymers. Plastics are artificial polymers. Most of the small molecules which make up biological polymers contain nitrogen atoms. Amino acids and polypeptides are two biological molecules which contain nitrogen. They are used to make proteins and DNA.

Nitrogen is one of the components of amino acids, the building blocks of proteins.

Yep. It's found in nucleic acids and in proteins.

our most part of body made by protien.

nitrogen is mainpart of protien.

protien is product of aminoacids.

formula of protien

H

I

NH2-C-R

I

nitrogen is also part of genes.