Which surface is better adapted for gas exchange in plant leaves?

In which of the following are stomata absent?

In an experiment demonstrating the evolution of oxygen in $Hydrilla$,sodium bicarbonate is added to water in the experimental set-up. What would happen if all other conditions are favourable?

Identify the incorrect sentences:
$(I)$ Humidity in the atmosphere is relatively higher in areas where light becomes a limiting factor for plants.
$(II)$ An increase in light intensity beyond a certain point causes the breakdown of chlorophyll,leading to a decrease in the rate of photosynthesis.
$(III)$ $C_4$ plants respond to higher temperatures and show higher rates of photosynthesis,while $C_3$ plants have a much lower temperature optimum.

Transpiration ratio is the ratio of moles of ${H_2}O$ transpired to moles of $CO_2$ fixed. This ratio is a measure of:

In cold and foggy areas,the limiting factor for photosynthesis is