Final answer:
Nitrogen gas constitutes 78% of the Earth's atmosphere and is crucial for life, tied up in proteins and genetic materials. It is acquired primarily through the fractional distillation of liquid air but is difficult for organisms to utilize due to its strong triple bond.
Step-by-step explanation:
Nitrogen gas does indeed make up the bulk of our atmosphere, being the most abundant gas present. Accounting for 78% of the atmosphere by volume, nitrogen is essential as it plays a vital role in various biochemical processes. The large quantity of nitrogen, more than 20 million tons over every square mile of the earth's surface, is primarily obtained through the fractional distillation of liquid air. This diatomic molecule is also a significant component of proteins and genetic material, found in DNA/RNA of plants and animals. However, the strength of the covalent triple bond in molecular nitrogen (N₂) makes it a challenge for living organisms to utilize directly, necessitating processes such as nitrogen fixation to convert it into a more usable form.