Nitrates of soil are also leached deep into the earth by . . . . . . .

Which of the following is considered to be the best chemical method of fixing atmospheric nitrogen?

Study the following columns and choose the correct match.

Column-$I$	Column-$II$
$(A)$ Photolysis of water	$(1)$ Zinc
$(B)$ Diazotrophy	$(2)$ Copper
$(C)$ Cytochrome-c oxidase	$(3)$ Manganese
$(D)$ Biosynthesis of $IAA$	$(4)$ Molybdenum
	$(5)$ Boron

$A$: Plants absorb nitrogen from the soil in the form of salts.
$R$: Nitrogen is essential for the synthesis of proteins and nucleic acids.

Match the following and choose the correct combination from the given options.

Column-$I$	Column-$II$
$(A)$ Potassium	$(1)$ Constituent of ferredoxin
$(B)$ Sulphur	$(2)$ Involved in stomatal movement
$(C)$ Molybdenum	$(3)$ Needed in the synthesis of auxin
$(D)$ Zinc	$(4)$ Component of nitrogenase

Statement $P$: In vertebrates,about $70$ percent of the total phosphorus is incorporated into bones and teeth.
Statement $Q$: Phosphorus is a structural component of vitamins like biotin and thiamine.