In which of the following plants would metabolism be hindered if the leaves are coated with wax on their upper surface?

Assertion : The atmospheric concentration of $CO_2$ at which photosynthesis just compensates for respiration is referred to as $CO_2$ compensation point.
Reason : The $CO_2$ compensation point is reached when the amount of $CO_2$ uptake is less than that generated through respiration because the level of $CO_2$ in the atmosphere is more than that required for achieving $CO_2$ compensation point.

Solarization is a phenomenon in which .....

Water budget (transpiration ratio) required to produce $1$ gm of dry matter by $C_3$ and $C_4$ plants is approximately:

Solarisation is

If the carbon dioxide content of the atmosphere is as high as $300 \, ppm$,what will be the effect on plants?