For the synthesis of one molecule of hexose,how many additional molecules of $ATP$ are required in $C_3$ and $C_4$ pathways,respectively,besides the $12$ molecules of $NADPH_2$?

$A$ : Most of the photosynthesis takes place in the blue and red regions of the spectrum.
$R$ : Action spectrum shows the amount of energy of different wavelengths of light absorbed by pigments.

During photosynthesis,$H_2O$ undergoes $.............$ and $CO_2$ undergoes $.............$.

The most vital process for the existence of life on earth is

Consider the following statements regarding photosynthesis:
$(A)$ $ATP$ formation during photosynthesis is termed as photophosphorylation.
$(B)$ Kranz anatomy pertains to leaf.
$(C)$ Reduction of $NADP^+$ to $NADPH$ occurs during Calvin cycle.
$(D)$ In a chlorophyll molecule,magnesium is present in the phytol tail.
Which of the above statements are correct?

Which would do maximum harm to a tree?