Which one of the following is a wrong statement?

1.	Anabaena and Nostoc are capable of fixing nitrogen in a free-living state also
2.	Root nodule-forming nitrogen fixers live as aerobes under free-living conditions
3.	Phosphorus is a constituent of cell membranes, certain nucleic acids, and all proteins
4.	Nitrosomonas and Nitrobacter are chemoautotrophs

An element playing important role in nitrogen fixation is:

1. molybdenum

2. copper

3. manganese

4. zinc

The function of leghemoglobin in the root nodules of legumes is:
1. oxygen removal
2. nodule differentiation
3. expression of nif gene
4. inhibition of nitrogenase activity

Which one of the following is not a micronutrient?

1. Molybdenum

2. Magnesium

3. Zinc

4. Boron

The free-living, anaerobic nitrogen-fixer is:

1. Beijerinckia

2. Rhodospirillum

3. Rhizobium

4. Azotobacter

Manganese is required in:
1. nucleic acid synthesis
2. plant cell wall formation
3. photolysis of water during photosynthesis
4. chlorophyll synthesis

Which of the following is a symbiotic nitrogen fixer?
1. Glomus
2. Azotobacter
3. Frankia
4. Azolla

Which one of the following elements is not an essential micronutrient for plant growth?
1. Mn
2. Zn
3. Cu
4. Ca