The process in which nitrogen is converted into a usable form for life is called
a. nitrogen fixation
b. photosynthesis
c. greenhouse effect
d. photolysis

Answer is (a) - nitrogen fixation

Nitrogen is an important element for living organisms. Free living or symbiotic bacteria help to convert the atmospheric nitrogen (form of atmospheric N is N₂) into usable form for living organisms naturally. This is called nitrogen fixation. Examples for some of them are Rhizobium, Azotobacter and some of Cyanobacteria.

pla·gia·rism

/ˈplājəˌrizəm/

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noun

the practice of taking someone else's work or ideas and passing them off as one's own.

explanation: