State the usefulness of ammonia in plants.

(N/A) Ammonia $(NH_3)$ is a vital source of nitrogen for plants.
$1$. It is the primary form of nitrogen that plants can assimilate into organic compounds.
$2$. Through the process of reductive amination,ammonia reacts with $\alpha$-ketoglutaric acid to form glutamic acid,which serves as the precursor for the synthesis of other amino acids via transamination.
$3$. It is also involved in the formation of amides like asparagine and glutamine,which are the structural components of proteins and serve as a transport mechanism for nitrogen within the plant.