What protects enzyme nitrogenase ?

Enzyme nitrogenase is

Enzyme nitrogenase is

The enzyme nitrogenase is

The enzyme nitrogenase is

Besides providing pink colour to the root nodules, leghaemoglobin performs the function of 1. protecting enzyme nitrogenase from free oxygen 2. transporting nitrogen to host cells 3. protecting bacteroids from the enzymes of host cell 4. protecting leakage of fixed nitrogen to the soil atmosphere

The correct inorganic contact of enzyme nitrogenase is

The correct inorganic contact of enzyme nitrogenase is

Name the oxygen seavenger molecule that protects nitrogenase in nodules.