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 of the following is a flowering plant with nodules containing filamentous nitrogen-fixing microorganism?

1. Casuarina equisetifolia

2. Crotolaria juncea

3. Cycas revoluta

4. Cicer arietinum