Major utilisation of carbon from the atmosphere is through

Consider the following statements.
$I.$ The portion of the spectrum between $300-500 \;nm$ is also referred to as Photosynthetically Active Radiation $(PAR)$.
$II.$ Magnesium,calcium and chloride ions play prominent roles in the photolysis of water.
$III.$ In cyclic photophosphorylation,oxygen is not released (as there is no photolysis of water) and $NADPH$ is also not produced.

Which would do maximum harm to a tree?

Provide the differences between:
$(1)$ Light reaction (Light phase) and Dark reaction (Biosynthetic phase)
$(2)$ Mesophyll cells and Bundle sheath cells

Which of the following is true for photosynthesis?

Read the following table and choose the correct pair.
$I$. $DCMU$ Herbicide: Inhibitor of non-cyclic electron transport
$II$. $PMA$ Fungicide: Reduces transpiration
$III$. Colchicine Alkaloid: Causes male sterility
$IV$. Soilrite Sodium alginate: Encapsulation of somatic embryos