AP BIOLOGY

Detailed explanation-1: -The third stage, nitrification, also occurs in soils. During nitrification the ammonia in the soils, produced during mineralization, is converted into compounds called nitrites, NO2−, and nitrates, NO3−.

Detailed explanation-2: -Nitrification. Nitrification is the process that converts ammonia to nitrite and then to nitrate and is another important step in the global nitrogen cycle.

Detailed explanation-3: -Nitrification: The conversion of ammonia into nitrate is called nitrification. It is carried out by some autotrophic bacteria such as Nitrosomonas, and Nitrococcus.

Detailed explanation-4: -Denitrification. Denitrification is the process in which the nitrogen compounds make their way back into the atmosphere by converting nitrate (NO3-) into gaseous nitrogen (N). This process of the nitrogen cycle is the final stage and occurs in the absence of oxygen.

Detailed explanation-5: -Nitrification is the biological conversion of ammonia or ammonium to nitrite followed by the oxidation of the nitrite to nitrate. The process of conversion of atmospheric nitrogen to forms that are usable for the plants is termed as nitrogen fixation.