If you have carefully read the role of macronutrients in your NCERT, you should be able to tell the name of the mineral that plays an important role in several carbon dioxide transfers catalyzed by carboxylase enzymes. The mineral is:
1. Magnesium
2. Sulfur
3. Iron
4. Calcium

Primary macronutrients are heavily used by plants. Based on your understanding of role of macronutrients , section 12.2.2, NCERT, can you predict which of the following may be a secondary macronutrient for plants?
1. Nitrogen
2. Phosphorus
3. Potassium
4. Calcium

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

Reaction carried out by ${\mathrm{N}}_2$ fixing microbes include
(i) 2NH₃ + 3O₂ \(\rightarrow\) \(2NO_2^-\) + 2H⁺ + 2H₂O 
(ii) \(2NO_2^-\) + O₂ \(\rightarrow\) 2NO₃
Select the false statement:
1. (i) is carried out by Nitrosomonas or Nitrococcus
2. (ii) is carried out by Nitrobacter
3. Both (i) and (ii) can be called nitrification
4. Bacteria carrying out (i) and (ii) are usually photoautotrophs

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. 

Match the element with its associated functions/roles and choose the correct option among given below:

Options:

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

Growing plants being suspended in a closed or semi-closed environment by spraying the plant's dangling roots and lower stem with an atomized or sprayed, nutrient-rich water solution is called as:
1. Hydroponics
2. Aquaponics
3. Aeroponics
4. In vitro culture

Plant growing in absence of light will show increased:
1. uptake of minerals
2. uptake of water
3. elongation of internodes
4. ascent of sap

Carnivorous plants are almost entirely restricted to habitats like bogs where:

1. soil nutrients are extremely limiting, but where sunlight and water are readily available.

2. soil has very low nitrogen but other minerals are adequate and there is shortage of sunlight.

3. soil nutrients, sunlight and water are all in very limited supply.

4. soil nutrients are readily available, but where sunlight and water are extremely limiting.