Symptoms of excess of manganese may actually be the deficiency symptoms of all the following except:

1. Iron	2. Magnesium
3. Calcium	4. Sulfur

Absorption of elements by plants happens in two phases where:
1. The first phase is rapid into the apoplast and is passive and the second phase is slow into the symplast and is active.
2. The first phase is slow into the apoplast and is passive and the second phase is rapid into the symplast and is active.
3. The first phase is slow into the apoplast and is active and the second phase is rapid into the symplast and is passive.
4. The first phase is rapid into the apoplast and is active and the second phase is slow into the symplast and is passive.

In plants with nitrogen fixing bacteria (such as alfalfa or soybeans), the presence of oxygen will poison the bacterium. Which of the following acts as a natural defense against oxygen toxicity by scavenging free oxygen in these systems?

Identify a free living anaerobic nitrogen fixing microbe:

Conversion of ammonium to nitrate during nitrogen cycle is called as:
1. Nitrogen assimilation
2. Denitrification
3. Nitrification
4. Nitratification

A microbially facilitated process of dissimilatory nitrate reduction that may ultimately produce molecular nitrogen (${\mathrm{N}}_2$) through a series of intermediate gaseous nitrogen oxide products is called as:

For biological fixation of one molecule of nitrogen into two molecules of ammonia, the number of ATP molecules needed is:

Name the amino acid from which 17 other amino acids are formed by transamination in plants?

Which one of the following statements can best explain the term critical concentration of an essential element?
1. Essential element concentration below which plant growth is retarded.
2. Essential element concentration below which plant growth becomes stunted.
3. Essential element concentration below which plant remains in the vegetative phase.
4. None of the above

With regard to the Biological Nitrogen Fixation by Rhizobium in association with soyabean, which one of the following statement/statements does not hold true?
1. Nitrogenase may require oxygen for its functioning .
2. Nitrogenase is MO-Fe protein.
3. Leg-hemoglobin is a pink coloured pigment.
4. Nitrogenase helps to convert ${\mathrm{N}}_2$ gas into two molecules of ammonia.