- 9 months ago
The First option is correct
The Atmospheric nitrogen is in the form of N2 which cannot be used directly by plants, thus it has to be fixed first either by lightning or nitrogen fixing bacteria like cyanobacteria, thus convertinh N2 into Ammonia.
Nitrification is the biological oxidation of ammonia or ammonium to nitrite followed by the oxidation of the nitrite to nitrate.
Assimilation is the process by which plants and animals incorporate the NO3- and ammonia formed through nitrogen fixation and nitrification.
Ammonification refers to any chemical reaction in which NH2 groups are converted into ammonia or its ionic form, ammonium (NH4+), as an end product.