Here's why:

* Amino acids are the building blocks of proteins.

* Proteins are essential components of living organisms, playing roles in structure, function, and regulation.

* Cysteine is an amino acid containing sulfur.

* Methionine is another amino acid containing sulfur.

* Glutamine and Asparagine are amino acids containing nitrogen.

Therefore, sulfur and nitrogen are found together in the chemical structure of amino acids, which are fundamental to all living organisms.