Question

The most important element associated with protoplasm and proteinaceous materials of plants is

Answer 1

Proteins are macromolecules synthesized from Nitrogen containing monomers; the amino acids. The amino acids have Nitrogen in the amino group attached to the $\alpha$-carbon atom. Basic amino acids have more than one amino groups present in their structure. Thus, nitrogen is the most important element required for synthesis of proteinaceous materials.

So, the correct answer is 'Nitrogen'