Root nodules contain

Nitrogenase enzyme is found in $Nostoc$ in the cell of:

Which of the following statements is correct regarding nitrogen fixation in legumes?

Knot-like bodies known as 'nodules' found in the roots of groundnut plant are produced by

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

Trace the events starting from the coming in contact of Rhizobium to a leguminous root till nodule formation. Add a note on the importance of leghemoglobin.