Question

The level of element X in the soil is increased with the help of bacterium Rhizobium. Name the element X.

• A. Nitrogen
• B. Ozone
• C. Chlorine
• D. Hydrogen

Answer 1

The correct option is A

Nitrogen

Nitrogen is an essential element for the growth of plants. But most plants are not able to get nitrogen on their own.

But few plants called legumes (like peas) have a certain bacteria in their roots. These bacteria absorb nitrogen and convert it to compounds which can be used by plants. This is called 'fixing' the nitrogen or nitrogen fixation. This process increases the levels of nitrogen in the soil which can be used by other nearby plants which don't have these bacteria.