Observe the diagram given above and answer the following questions.
(a) Name the technique shown in the figure.
(b) Name any two plants for which this technique can be emplhyed for their commercial production.
(c) Mention the purpose for which
(i) the feeding funnel and
(ii) the aeration tube are used in this experimental set-up.

The picture given above shows hydroponic plant production, where plants are grown in a tube that is kept on a slight incline.
(a) What is the role of the pump in this experiment?
(b) What do the arrows indicate?
(c) Name the scientist who first showed that plants could be grown to maturity in defined nutrient solution.

Plants absorb a number of elements from the soil; about sixty elements are found in different plants. But, studies with reference to mineral nutrition and metabolism have shown that all the elements absorbed are not essential for the plants. Scientists like Arnon, have listed the essential elements based on certain criteria.
Write the three criteria of essentiality of elements in plant nutrition.

The micronutrients are always required in minute or trace quantities; their moderate decrease in quantity causes deficiency symptoms to appear while their moderate increase in quantity causes toxicity.
(a) What is meant by toxicity of an element?
(b) How does manganese toxicity cause deficiency symptoms of
(i) iron and
(ii) magnesium?

Given below is the flow chart of the nitrogen cycle showing the relationship among the three main nitrogen pools, i.e. atmospheric, biomass and soil. Study the diagram and answer the questions that follow:

(a) Fill in the blanks, A, B, C and D.
(b) Name two bacteria that carry out the step A.
 

An example of one of the methods of synthesis of amino acids in plants is shown below. Answer the questions that follow:

(a) Name the process of synthesis of amino acid shown above.
(b) Fill in the blanks \(\begin{array}{|l|} \hline \mathrm{A} \\ \hline \end{array}\) , \(\begin{array}{|l|} \hline \mathrm{B} \\ \hline \end{array}\) and \(\begin{array}{|l|} \hline \mathrm{C} \\ \hline \end{array}\).
(c) Name the two most important amides in plants.