What was the fundamental limiting factor for life on Earth regarding nitrogen despite its high atmospheric concentration?

Answer

The ability to harness nitrogen due to its strong triple bond

Although the atmosphere is nearly 80 percent nitrogen gas ($ ext{N}_2$), its strong triple bond made it incredibly difficult to convert into biologically useful compounds like ammonia, which was the main limitation.

What was the fundamental limiting factor for life on Earth regarding nitrogen despite its high atmospheric concentration?
inventionwaterremovalprocessNitrogen