Methanogens (microorganisms producing methane) are found in the guts of ruminant animals e.g. cows and buffalloes.

Correct Option: B

Methanogens (microorganisms producing methane) are found in the guts of ruminant animals e.g. cows and buffalloes.

Saccharomyces cerevisiae commonly know as Brewer’s yeast, causes fermentation of carbohydrates and produces ethanol.

Correct Option: C

Saccharomyces cerevisiae commonly know as Brewer’s yeast, causes fermentation of carbohydrates and produces ethanol.

Primary treatment is a physical process which involves two process, i.e. filtration and sedimentation of big solid waste.

Correct Option: B

Primary treatment is a physical process which involves two process, i.e. filtration and sedimentation of big solid waste.

The common nitrogen fixer in paddy field is Azospirillum. It is an anaerobic bacteria that forms loose association with roots of paddy crops.

Correct Option: B

The common nitrogen fixer in paddy field is Azospirillum. It is an anaerobic bacteria that forms loose association with roots of paddy crops.

Azotobacter are nonsymbiotic, free living nitrogen fixing bacteria. (c) Azotobacter is a free living soil bacterium able to take up dinitrogen from the soil and fix it into organic nitrogenous material like aminoacid. Clostridium is anaerobic free living soil N₂ fixing bacteria. Rhizobium is symbiotic N₂ fixing bacteria.

Correct Option: A

Azotobacter are nonsymbiotic, free living nitrogen fixing bacteria. (c) Azotobacter is a free living soil bacterium able to take up dinitrogen from the soil and fix it into organic nitrogenous material like aminoacid. Clostridium is anaerobic free living soil N₂ fixing bacteria. Rhizobium is symbiotic N₂ fixing bacteria.