Photosynthesis is:
$I.$ Endergonic process
$II.$ Exergonic process
$III.$ Chemical process
$IV.$ Physical process
Select the correct option.

What percentage of usable radiant energy entering a reaction site of photosynthesis is converted to potential energy (in $\%$)?

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 $NADPH_2$?

Choose the incorrect sentences for chloroplast.
$(1)$ The chloroplast membranous system consists of grana and the fluid stroma.
$(2)$ Pigments are present in the stroma.
$(3)$ In the stroma,enzymatic reactions incorporate $CO_2$ into the plant,leading to the synthesis of sugar.
$(4)$ Light is not required for the formation of sugar in the stroma.

The importance of photosynthesis is due to

Blackman demonstrated that increasing illumination increased the photosynthetic rate up to a point when $CO_2$ becomes limiting. If light was not limiting,temperature becomes limiting. Emerson found that maximum $CO_2$ fixation could be achieved with brief flashes of light. Mark the correct statement in the following: