Describe one reason why nitrogen is crucial for sustaining life on Earth. Answer in at least 1 complete sentence.

Nitrogen is very crucial for life because it is one of the important ingredient that is needed for plants to grow. Human and animals who eat plants materials obtain nitrogen from the plant. Nitrogen is needed in the humans and animals bodies for formation of proteins and nucleic acid which are very essential for life. When animals and humans die the nitrogen in their bodies return to the earth again and is used by plants.