Differentiate between $C_3$ and $C_4$ plants.

For photosynthesis (i.e.,for synthesis of organic matter),the green plants need:

Why are green plants necessary for living organisms?

What is the quantum yield of photosynthesis (in $\%$)?

Choose the correct sentence$(s)$ from the following:
$(i).$ In $C_4$ plants,the first $CO_2$ acceptor is $PEP$.
$(ii).$ Light energy is absorbed by $PS-II$ at $680 \ nm$ in the process of photosynthesis.
$(iii).$ The $P_{680}$ chlorophyll system is present in $PS-I$.

$A-$ 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 $NADPH$.