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

Which bacteria live symbiotically on the root system of leguminous plants?

Which of the following statements is correct?

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.

Leguminous plants are able to fix atmospheric nitrogen through the process of symbiotic nitrogen fixation. Which one of the following statements is not correct during this process of nitrogen fixation?

Leguminous plants have the ability to fix atmospheric nitrogen through a symbiotic nitrogen fixation process. Which of the following statements is $NOT$ true regarding this process?