Question

__________is nitrogen fixing bacteria, while ________ as a denitrifying bacteria

• A. Clostridium, pseudomonas
• B. Nostoc, Azotobacter
• C. beggiatoa, rhizobium
• D. Methanogenes, beggiatoa

Answer 1

Answer:

A. Clostridium, pseudomonas

Nitrogen-Fixing Bacteria

Nitrogen-fixing bacteria convert atmospheric nitrogen gas (N2​), which plants cannot use, into a usable form like ammonia (NH3​). This process, known as nitrogen fixation, is a vital part of the nitrogen cycle. Clostridium is an example of a free-living, anaerobic bacterium that performs nitrogen fixation.

Denitrifying Bacteria

Denitrifying bacteria perform the reverse process. They convert nitrates (NO3−​), a form of nitrogen that is useful for plants, back into nitrogen gas (N2​), which is then released into the atmosphere. This process is called denitrification. Pseudomonas is a genus of bacteria that is well-known for its role in denitrification, especially in anaerobic environments.