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

The $C_4$ and $C_3$ plants differ from each other in

The process of uptake of $CO_2$ and release of $O_2$ by plants is called ...

Which of the following ions of heavy metals participate in the process of photosynthesis in higher plants?

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 $PS-I$.

When green algae are illuminated,motile aerobic bacteria usually accumulate near them. This is because,bacteria