Which one of the following is a wrong statement?
A. Root nudule forming nitrogen fixers live as aerobesunder free-living conditions.
B. Phosphorus is a constituent of cell membranes, certain nucleic acids, and all proteins.
C. Nitrosomonas and Nitrobacter are chemoautotrophs.
D. Anabaena and Nostoc are capable of fixing nitrogen in free-living state also.