Who first demonstrated the $C_4$ pathway?

In $C_4$ plants,$CO_2$ combines with $PEP$ in the presence of which enzyme?

As compared to a $C_{3}$-plant,how many additional molecules of $ATP$ are needed for the net production of one molecule of hexose sugar by $C_{4}$-plants?

Site of $C_3$ cycle in $C_4$ plants is $:-$

$CAM$ helps the plants in

What happens to $C_{4}$ acid in the bundle sheath cells?