Answer:
Nitrogen cycle works through various stages like, nitrogen fixation, nitrification, assimilation, ammonification, denitrification etc. It is a building block for protein and DNA
Explanation:
Nitrogen is an element abundantly found in the atmosphere, also its building block for proteins as well as nucleic acid i.e. DNA formation. In nitrogen cycle , the nitrogen is being prepared from inert nitrogen. The nitrogen cycle has several processes like nitrogen fixation, in this the inert nitrogen is being converted to organic nitrogen with the help of certain micro-organism.
Nitrification, plants cannot absorb directly nitrogen so bacteria help the plants to convert the nitrogen into ammonia form in this stage. Assimilation, another stage in which plants starts absorbing various forms of nitrogen from the soil.i.e. nitrate, nitrite and ammonium. Ammonification, here plants and animals have nitrogen in there body after death various microbes help in decomposition in this stage. Denitrification, in this stage the return back of nitrogen takes place.
A variation is a reference to the differences or deviations, such as the structure and form, as for crossing over is the exchange of genetic material between the non-sister chromatids of the homologous chromosomes during meiosis.
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