Question

Choose the correct definition for “Rhizobium bacteria”.

• A. The bacteria found in the intestines of animals which help in the digestion of cellulose present in their feed
• B. Bacteria which are used in sewage works to break down the organic matter in sewage and make it harmless
• C. The nitrogen-fixing bacteria present in root nodules of leguminous plants which convert atmospheric nitrogen gas into nitrogen compound
• D. Bacteria that makes curd from milk

Answer 1

The correct option is C The nitrogen-fixing bacteria present in root nodules of leguminous plants which convert atmospheric nitrogen gas into nitrogen compound

Rhizobium is a nitrogen-fixing bacteria. They are present in the root nodules of leguminous plants. In order to express genes for nitrogen-fixation, rhizobia require a plant host; they cannot independently fix nitrogen. Nitrogen fixation is a process by which nitrogen in the Earth's atmosphere is converted into ammonia $N{H}_3$ or other molecules available to living organisms.