In submerged hydrophytes,the entry of $CO_2$ is through:

Which statement about photosynthesis is false?

What is the effect of high $CO_{2}$ concentration and higher values of $ATP/ADP$ ratio?

Give scientific reasons:
$(1)$ The productivity of $C_4$ plants is more than $C_3$ plants.
$(2)$ It is necessary that the Calvin cycle runs for six times.

$A-$ In stroma,enzymatic reactions synthesize sugar which in turn forms starch.
$R-$ The membrane system of chloroplast is responsible for trapping the light energy and also for the synthesis of $ATP$ and $NADPH$.

State the site of the light reaction and dark reaction in photosynthesis,respectively.