Nitrifying bacteria are responsible for converting ammonia (NH3) to usable nitrates (NO3) and nitrites (NO2) in the Nitrogen Cycle. Hence the correct option is b.
In the nitrogen cycle, the conversion of ammonia (NH3) to usable nitrates (NO3) and nitrites (NO2) is facilitated by nitrifying bacteria. These specialized microorganisms play a crucial role in the cycle by carrying out two key processes: ammonia oxidation and nitrite oxidation. Ammonia-oxidizing bacteria first convert ammonia to nitrites (NO2), and then nitrite-oxidizing bacteria further transform nitrites into nitrates (NO3). This conversion is vital for making nitrogen compounds accessible to plants, as nitrates are a form of nitrogen that plants can uptake and utilize for their growth and development.
Therefore, nitrifying bacteria contribute to the essential transformation of nitrogen through the nitrogen cycle, facilitating the availability of nitrogen in a usable form for various organisms within ecosystems. The intricate interactions between bacteria and nitrogen compounds highlight the dynamic nature of nutrient cycling in natural environments. Hence the correct option is b.