$Nif$ genes occur in

$A -$ The enzyme nitrogenase is highly sensitive to molecular oxygen.
$R -$ To protect nitrogenase enzymes,the nodule contains an oxygen scavenger called leghaemoglobin.

What is the function of leghemoglobin in the root nodules of Leguminosae?

Which specific enzyme is present in the heterocysts of blue-green algae?

Which of the following is a free-living,aerobic,non-photosynthetic nitrogen-fixer?

What is impossible if nitrogenase is inactivated by radiation?