What does nitrogen fixational accomplish

Nitrogen fixation refers to the conversion of atmospheric nitrogen gas (N2) into a form usable by plants and other organisms.

Nitrogen Fixation refers to the process of conversion of atmospheric nitrogen gas to usable form by living organisms.

Explanation:

NH3, i. e. fixed form of Nitrogen is an important component of DNA and proteins which is needed by living organisms.

The biological conversion of Nitrogen happens by conversion of Nitrogen in the atmosphere, i. e. N2 is converted to ammonia, NH3. This is performed by "Nitrogen-fixing bacteria". They play a major part in the "nitrogen cycle" by converting "atmospheric nitrogen" into 'fixed' nitrogen which can actually be used by living organisms, be it plants, humans or animals.