Nitrogen is present in the soil in the form of
$I.$ Nitrates $II.$ Ammonium salts
$III.$ Nitrite $IV.$ None of these

Nitrifying bacteria perform which of the following processes?

Select the correct matches.
$I$ Nitrosomonas - Nitrite to nitrate
$II$ Thiobacillus - Denitrification
$III$ Nostoc - Free-living nitrogen-fixer
$IV$ Azotobacter - Anaerobic nitrogen-fixer

Plants usually absorb Nitrogen in the form of nitrates because Nitrogen is . . . . . . .

What is the function of nitrifying bacteria?

The process of conversion of nitrogen gas into ammonia is called $P$,and the process of decomposition of organic nitrogen in plants and animals into ammonia is called $Q$.