What is the process of combining nitrogen with oxygen or hydrogen to make it usable to organisms?

The process of combining nitrogen with oxygen or hydrogen to make it usable to organisms is known as nitrogen fixation. This occurs naturally through lightning strikes or by certain bacteria in the soil and roots of legumes, which convert atmospheric nitrogen (N₂) into ammonia (NH₃) or related compounds. These forms of nitrogen can then be taken up by plants and used to synthesize amino acids and nucleotides, which are essential for life. Additionally, industrial processes, like the Haber-Bosch method, also synthesize ammonia for fertilizers, further facilitating nitrogen's availability to organisms.