Plants can be grown in (Select the incorrect option)
1. Soil with essential nutrients
2. Water with essential nutrients
3. Either water or soil with essential nutrients
4. Water or soil without essential nutrients

A symptom common to the deficiency of Ca, Mg, Cu and K in plants is:
1. Chlorosis
2. Inhibition of cell division
3. Necrosis
4. Delay in flowering

Majority of the nutrients that are essential for the growth and development of plants become available to the roots due to:
1. Microbial actions in the soil
2. Wet deposition from the atmosphere
3. Addition of fertilizers
4. Weathering and breakdown of rocks

Nitrogen fixation means:
1. releasing nitrogen from dead and decaying materials.
2. conversion of nitrite to nitrate.
3. conversion of nitrate to nitrite.
4. conversion of nitrogen gas into ammonia.

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. 

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

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

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

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:

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