The correct option is A True
∙ Rhizobium helps in fixing atmospheric nitrogen. It takes nitrogen from atmosphere and fixes in the roots of plants. In turn, plant gives shelter to the bacterium. Thus, both help each other and this relationship is known as symbiosis. The plant serves as a host for them and in return for the nitrogen fixed by the Rhizobium, the plant provides nutrition to it.
∙ They are present in the root nodules of leguminous plants such as, peas and lentils and do nitrogen fixation and in turn, get shelter in their roots.