Which element plays an important role in nitrogen fixation?

Which mineral elements are important for the maintenance of the osmotic pressure of intracellular fluids?

Match List-$I$ with List-$II$:

List-$I$	List-$II$
$A$. Iron	$I$. Synthesis of auxin
$B$. Zinc	$II$. Component of nitrate reductase
$C$. Boron	$III$. Activator of catalase
$D$. Molybdenum	$IV$. Cell elongation and differentiation

Choose the correct answer from the options given below:

Which of the following elements helps in maintaining the structure of ribosomes?

Which of the following is an incorrect statement?

$S$ - Statement: Sulfur is present in the structure of cysteine and methionine amino acids.
$R$ - Reason: Phosphorus does not participate in energy exchange processes.