The product(s) of the reaction catalyzed by nitrogenase in root nodules of leguminous plants is/are.

1. Nitrate alone

2. Ammonia and oxygen

3. Ammonia and hydrogen

4. Ammonia alone

Thiobacillus is a group of bacteria helpful in carrying out:

1. Denitrification

2. Nitrogen fixation

3. Chemoautotrophic fixation

4. Nitrification