....... activates various enzymes,especially carboxylases.

The micronutrient least required by plants is

$P$: Phosphorus is essential for normal growth and reproduction in our body.
$Q$: Copper is important in the synthesis of chlorophyll in plants.

Assertion $A$: Copper is essential for the synthesis of chlorophyll in plants.
Reason $R$: Magnesium is located at the central part of the chlorophyll structure.
Which option is correct for Assertion $A$ and Reason $R$?

Which element is essential for the growth of the pollen tube?

Match List-$I$ with List-$II$.

List-$I$	List-$II$
$(a)$ Manganese	$(i)$ Activates the enzyme catalase
$(b)$ Magnesium	$(ii)$ Required for pollen germination
$(c)$ Boron	$(iii)$ Activates enzymes of respiration
$(d)$ Iron	$(iv)$ Functions in splitting of water during photosynthesis