The symbiotic nitrogen-fixing bacteria present in root nodules of legumes belong to the genus

Arrange the stages of root nodule formation in the correct sequence:
$I-$ Infection thread is produced.
$II-$ Bacteria are carried to the cortex of the root.
$III-$ Bacteria attach to the root hair.
$IV-$ Bacteria are released from the thread into the cells.
$V-$ Differentiation into nitrogen-fixing cells occurs.

The bacteria found in the root nodules of the family $Leguminosae$ are:

Symbiotic nitrogen fixation in non-leguminous plants is carried out by

Which microorganisms live symbiotically on leguminous plants?

Explain the stages of root nodule formation.