Rhizobium lives symbiotically with root nodules and fixes atmospheric nitrogen. It provides nitrogenous compounds to the host and in turn takes food from the host. This food taken by the bacterium is:

Explain the stages of root nodule formation.

Assertion : Leguminous plants are nitrogen fixers.
Reason : Leguminous plants have $Rhizobium$ in their root nodules.

What is the function of leghemoglobin?

Nitrogen fixation in the root nodules of $Alnus$ is performed by:

We find that $Rhizobium$ forms nodules on the roots of leguminous plants. Also,$Frankia$,another microbe,forms nitrogen-fixing nodules on the roots of the non-leguminous plant $Alnus$. What kind of relationship is observed between mycorrhiza and pine trees?