Which of the following plays a prominent role in leaf growth?

Read the functions given below and identify the concerned nutrient.
$I.$ Activator of catalase
$II.$ Important constituent of cytochrome
$III.$ Important constituent of proteins involved in $ETS$
$IV.$ Essential for chlorophyll synthesis

Which mineral element is present in the structure of hemoglobin,myoglobin,and cytochrome compounds?

An element playing an important role in nitrogen fixation is:

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

In green plants,boron is required for: