Plants do not get benefit from

(1) N₂ in air

(2) O₂ in air

(3) CO₂ in air

(4) O₃ in air.

Which of the following set of elements are essential for the photosynthesis to occurs

(1) Cu, Co, Fe

(2) Cu, Mo, Zn

(3) Mg, Co, Mn

(4) Mg, Fe, Mn, Cu, Cl, P

Which enzyme complex is responsible for the reduction of molecular nitrogen to the level of NH₃ in

root module of legume?

(1) Aminase

(2) Nitrogenase

(3) Nitrate reductase

(4) Nitrite reductase

Leghaemoglobin is produced in response to

1. respiration 

2. photosynthesis

3. fatty acid synthesis

4. N₂ fixation.
 

Which one of the following is not a microelement for plants?
(1) Cu

(2) B

(3) Zn

(4) Cr

Which of the following is correct set of micronutrient for plants?

1. Mg, Si Fe, Cu Ca

2. Cu, Fe, Zn, B, Mn

3. Mg, Fe, Zn, B, Mn

4. Mo, Zn, Cl, Mg, Ca

The function of leghaemoglobin during biological nitrogen fixation in root nodules of legumes is to
1. convert atmospheric N₂ to NH₃
2. convert ammonia to nitrite
3. transport oxygen for activity of nitrogenase
4. protect nitrogenase from oxygen.

Hydroponics is

1. cultivation of plants in water

2. growth of plants towards water

3. growth of plants away from water

4. soilless cultivation of plants